OSEEN’S CORRECTION TO STOKES DRAG ON AXIALLY SYMMETRIC ARBITRARY PARTICLE IN TRANSVERSE FLOW: A NEW APPROACH Deepak Kumar Srivastava Nirmal Srivastava Theoret.Appl.Mech. TEOPM7, Vol.41, No.3, pp. 177–212, Belgrade 2014 * * doi:10.2298/TAM1403177S Math. Subj. Class.: 76D07. According to: Tib Journal Abbreviations (C) Mathematical Reviews, the abbreviation TEOPM7 stands for TEORIJSKA I PRIMENJENA MEHANIKA.
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OSEEN’S CORRECTION TO STOKES DRAG ON AXIALLY
SYMMETRIC ARBITRARY PARTICLE IN TRANSVERSE
FLOW: A NEW APPROACH
Deepak Kumar Srivastava Nirmal Srivastava
Theoret.Appl.Mech. TEOPM7, Vol.41, No.3, pp. 177–212, Belgrade 2014 ∗
According to: Tib Journal Abbreviations (C) Mathematical Reviews, the abbreviation TEOPM7 standsfor TEORIJSKA I PRIMENJENA MEHANIKA.
Oseen’s correction to Stokes drag on axiallysymmetric arbitrary particle in transverse flow:
a new approach
Deepak Kumar Srivastava ∗ Nirmal Srivastava †
Theoret. Appl. Mech., Vol.41, No.3, pp. 177–212, Belgrade 2014
Abstract
In this paper, Oseen’s correction to Stokes drag experienced by axiallysymmetric particle placed in a uniform stream perpendicular to axis ofsymmetry(i.e. transverse flow) is obtained. For this, the linear relation-ship between axial and transverse Stokes drag is utilized to extend theBrenner’s formula for axial flow to transverse flow. General expressionof Oseen’s correction to Stokes drag on axially symmetric particle placedin transverse flow is found to be new. This general expression is appliedto some known axially symmetric bodies and obtained values of Oseen’sdrag, up to first order terms in Reynolds number ‘R’, are also claimed tobe new and never exist in the literature. Numerical values of Oseen dragare also evaluated and their variations with respect to Reynolds num-ber, eccentricity and deformation parameter are depicted in figures andcompared with some known values. Some important applications are alsohighlighted.
The method and formulation for analysis of flow at a very low Reynolds num-ber is important. The slow motion of small particles in a fluid is commonin bio-engineering. Oseen’s drag formulation can be used in connection withflow of fluids under various special conditions, such as: containing particles,
∗Department of Mathematics B.S.N.V. Post Graduate College(University of Luc-know, Lucknow) Station Road, Charbagh, Lucknow (U.P.)-226001, India, e-mail: [email protected]
sedimentation of particles, centrifugation or ultracentrifugation of suspensions,colloids, and blood through isolation of tumors and antigens. The fluid doesnot even have to be a liquid, and the particles do not need to be solid. It can beused in a number of applications, such as smog formation and atomization ofliquids.The problem of great importance in the hydrodynamics of low Reynoldsnumber flows is the drag or resistance experienced by a particle moving uni-formly through an infinite fluid. Since the appearance of Stokes’s approximatesolution for the flow of a viscous fluid past a sphere(Stokes, 1851), very wellknown as Stokes law, numerous attempts have been made, both to generalizethe problem by changing the shape of the body, and to improve the calculationby including the effect of the inertia terms which were neglected in the originalcalculation. Oseen(1927) tackled this type of problem involving the correctionto Stokes drag extensively. Oseen provided solutions for the flow past variousbodies at small Reynolds number ‘R’ and calculated the force to the first orderin R, one term more than would be given by the Stokes approximation. Bythe inclusion of the effect of the inertia terms, Oseen improved the flow picturefar from the body where the Stokes approximation is inadequate, but nearthe body the difference between the two solutions is of an order of smallnesswhich is outside the accuracy of either approximation. Oseen’s calculation forthe force thus requires some further justification, for flow past a sphere, bythe work of Kaplun(1957), Kaplun and Lagerstrom(1957) and Proudman andPearson(1957). Oseen failed to calculate correctly the velocity field, his resultfor the drag on the sphere, namely
D = D0[1 + (3/8)R], (1.1)
where D0 is the Stokes drag, is in fact valid because the correction to the veloc-ity field makes no contribution to the total force on the sphere. Almost similarproblem has been considered by Chang (1960) for the axially symmetric Stokesflow of a conducting fluid past a body of revolution in the presence of a uni-form magnetic field. An equation identical to that cited above, except that thedimensionless Hartmann number, M, appears in place of the Reynolds num-ber, ‘R’. It is interesting to note here that Chang’s(1960) result is restricted toaxially symmetric flows because of the requirement that there be sufficient sym-metry to preclude the existence of an electric field. While, on the other hand,Brenner’s(1961) result is limited only by the requirement that the Stokes dragon the particle(and thus the Oseen drag) be parallel to its direction of motion.Krasovitskaya et al.(1970) proposed a formula based on Oseen’s correction forcalculating the settling of solid particles of powdered materials with enhancedaccuracy in carrying out sedimentation analysis. Dyer and Ohkawa(1992) have
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...179
used the Oseen drag in acoustic levitation. These two works are the main prac-tical applications of Oseen’s correction which was not possible with the Stokesdrag. In biology(Fung, 1997), blood flow in small vessels, such as capillaries, ischaracterized by small Reynolds numbers. A vessel of diameter of 10 m with aflow of 1 milimetre/second, viscosity of 0.02 poise for blood, density of 1 g/cm3and a heart rate of 2 Hz, will have a Reynolds number of 0.005. At these smallReynolds numbers, the viscous effects of the fluid become predominant. Os-een’s method is better in understanding of the movement of these particles fordrug delivery and studying metastasis movements of cancers.
Datta and Srivastava(1999) have proposed a new method to evaluate axialStokes drag and transverse Stokes drag based on geometry of axially symmet-ric particle under no-slip boundary condition. From these two expressions ofStokes drag, the linear relationship between axial and transverse Stokes dragcan be proved. With the help of this linear relationship, we can evaluate theOseen’s correction in Stokes drag experienced by axially symmetric particlesplaced in transverse flow followed by Brenner’s formula(Brenner, 1961). Sri-vastava et al.(2012) solved the problem of steady Stokes flow past dumbbellshaped axially symmetric body of revolution by using newly developed analyticapproach based on D-S conjecture(Datta and Srivastava, 1999). The methodis described in section 2 and applied to various axially symmetric bodies insection 4.
2 Method
Let us consider the axially symmetric body of characteristic length L placedalong its axis (x-axis, say) in a uniform stream U of viscous fluid of density ρand kinematic viscosity ν. When Reynolds number UL/ν is small, the steadymotion of incompressible fluid around this axially symmetric body is governedby Stokes equations [Happel and Brenner, 1964],
0 = −(1
ρ
)gradp + ν∇2u, div u = 0 (2.1)
subject to the no-slip boundary condition.
We have taken up the class of those axially symmetric bodies which pos-sesses continuously turning tangent, placed in a uniform stream U along theaxis of symmetry (which is x-axis), as well as constant radius ’b’ of maximumcircular cross-section at the mid of the body. This axi-symmetric body is ob-tained by the revolution of meridional plane curve (depicted in figure 1) about
180 Deepak Kumar Srivastava & Nirmal Srivastava
axis of symmetry which obeys the following limitations:
i. Tangents at the points A, on the x-axis , must be vertical,
ii. Tangents at the points B, on the y-axis , must be horizontal,
iii.The semi-transverse axis length ’b’ must be fixed.
The point P on the curve may be represented by the Cartesian coordinates(x, y) or polar coordinates (r, θ) respectively; PN and PM are the length oftangent and normal at the point P. The symbol R stands for the interceptinglength of normal between the point on the curve and point on axis of symmetryand symbol α is the slope of normal PM which can vary from 0 to π.
Figure 1: Geometry of axially symmetric body
2.1 Axial flow
The expression of Stokes drag on such type of axially symmetric bodies placedin axial flow (uniform flow parallel to the axis of symmetry) is given by [Dattaand Srivastava, 1999]
Fx =1
2
λb2
hx, where λ = 6πµU (2.2)
and hx =
(3
8
)∫ π
0Rsin3αdα. (2.3)
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...181
2.2 Transverse flow
The expression of Stokes drag on axially symmetric bodies placed in transverseflow(uniform flow perpendicular to the axis of symmetry) is given by [Dattaand Srivastava, 1999]
Fy =
(1
2
)λb2
hy, where λ = 6πµU (2.4)
and hy =
(3
16
)∫ π
0R(2sinα− sin3α
)dα. (2.5)
Here the suffix ‘y’ has been introduced to assert that the force is in the trans-verse direction,
Fx
Fy=
hyhx
=1
2
∫ π0 R
(2sinα− sin3α
)dα∫ π
0 Rsin3αdα= K (say). (2.6)
Now, on dividing (2.2) and (2.4), we get
Fx = KFy. (2.7)
On applying Brenner’s formula (Brenner, 1961), Oseen’s correction to Stokesdrag on a body placed in axial uniform flow, in general, may be written as
F
Fx= 1 +
Fx
16πµLUR+O(R2), (2.8)
by using linear relationship between axial and transverse Stokes drag (2.7),equation (2.8) provides Oseen’s correction to Stokes drag on a body placed intransverse uniform flow
F
Fy= K
F
Fx= K
[1 +
Fx
16πµLUR+O(R2)
]. (2.9)
where K is a real factor defined in (2.6) and R = ρUL/µ, the particles Reynoldsnumber.
3 Formulation of the problem
Let us consider the axially symmetric arbitrary body of characteristic lengthL placed along its axis (x-axis, say) in a uniform stream U of viscous fluid ofdensity ρ and kinematic viscosity, perpendicular to axis of symmetry. When
182 Deepak Kumar Srivastava & Nirmal Srivastava
particle Reynolds number UL/ν is small, the steady motion of incompress-ible fluid around this axially symmetric body is governed by Stokes equations[Happel and Brenner, 1964],
0 = −(1
ρ
)gradp + ν∇2u, divu = 0, (3.1)
subject to the no-slip boundary condition. This equation is the reduced formof complete Navier–Stokes equations neglecting inertia term (u.grad)u whichis unimportant in the vicinity of body where viscous term dominates(Stokesapproximation). Solution of this equation (3.1), called Stokes law, ‘6πµUa’,for a slowly moving sphere having radius ‘a’, is valid only in the vicinity of thebody which breaks down at distance far away from the body. This breaks downin Stokes solution at far distance from the body being known as Whitehead’sparadox. It was Oseen in 1910, who pointed out the origin of Whitehead’sparadox and suggested a scheme for its resolution(see Oseen, 1927). In or-der to rectify the difficulty, Oseen went on to make the following additionalobservations.
In the limit where the particle Reynolds number ρUa/µ → 0, Stokes ap-proximation becomes invalid only when r/a → ∞. But at such enormous dis-tances, the local velocity v differs only imperceptibly from a uniform streamof velocity U. Thus, Oseen was inspired to suggested that the inertial term(U.grad)u could be uniformly approximated by the term (u.grad)u. By sucharguments, Oseen proposed that uniformly valid solutions of the problem ofsteady streaming flow past a body at small particle Reynolds numbers couldbe obtained by solving the linear equations
(U.grad)u = −(1
ρ
)gradp + ν∇2u, divu = 0 (3.2)
known as Oseen’s equation. Oseen obtained an approximated solution of hisequations for flow past a sphere, from which he obtained the Stokes drag for-mula [Happel and Brenner, page 44, eq.(2-6.5), 1964]
F = 6πµaU
[1 +
3
8NRe +O
(NRe
2)]
, (3.3)
where NRe = ϱUa/µ is bodies Reynolds number.We find the solution of these equations (3.2) for various axially symmetric
bodies like sphere, spheroid(prolate and oblate), deformed sphere, cycloidalbody, cassini oval, hypocycloidal body, cylindrical capsule with semi sphericalends and complicated egg-shaped body consisting of semi spherical and semi
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...183
spheroidal ends under no-slip boundary conditions by use of D-S conjecture(2.2), (2.4) followed by linear relationship (2.7) and Brenner’s formula (2.8)valid for axial flow and its extension (2.9) for transverse flow.
4 Solution
4.1 Flow past a sphere
Stokes drag on sphere having radius ‘a’ placed in uniform axial flow, withvelocity U, parallel to axis of symmetry(x-axis) and very well known as Stokeslaw of resistance is given by(by utilizing DS conjecture 2.4 and 2.5, Datta andSrivastava, 1999)
0 20 40 60 80 1000
5
10
15
20
25
30
35
40
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 2: Variation of Oseen correction with respect to Reynolds number R =ρUa/µ for sphere
Fx =6πµUa. (4.1a)
Fy =6πµUa. (4.1b)
184 Deepak Kumar Srivastava & Nirmal Srivastava
From relation (4.1a, b) and (2.7), the value of
K = 1. (4.2)
Now, the Oseen’s correction as well as the solution of Oseen’s equation (3.2)may be obtained for same sphere by substituting the value of K = 1 and Stokesdrag (4.1a,b) in Brenner’s formula (2.8) and (2.9) as
F
Fy=
F
Fx= 1 +
3
8R +O
(R2
), (4.3)
where R =(ρUaµ
)is particle Reynolds number. This Oseen’s correction
matches with that given by Oseen(1927) and Chester(1962).
4.2 Flow past a prolate spheroid
Stokes drag on prolate spheroid having semi-major axis length ‘a’ and semi-minor axis length ‘b’ placed in uniform velocity U, parallel to axis of symme-try(axial flow) and perpendicular to its axis of symmetry(transverse flow) isgiven as[by utilizing formulae 2.4 and 2.5, Datta and Srivastava, 1999]
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 3: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUa/µ for prolate spheroid
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...185
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 4: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUb/µ for prolate spheroid
Fx = 16πµUae3[−2e +
(1 + e2
)ln1 + e
1− e
]−1
, (4.3a)
Fy = 32πµUae3[2e +
(3e2 − 1
)ln1 + e
1− e
]−1
. (4.3b)
By using (4.3a,b), from (2.7), the value of real factor ‘K’ comes out to be
K =1
2
[2e +
(3e2 − 1
)ln1 + e
1− e
] [−2e +
(1 + e2
)ln1 + e
1− e
]−1
= 1− 1
10e2 − 8
175e4...
(4.4)
186 Deepak Kumar Srivastava & Nirmal Srivastava
Now, from Brenner’s formula (2.8) and (2.9), the Oseen’s correction, with theuse of real factor K (cf. (4.4)) may be written as
F
Fy= K
F
Fx
=
[1− 1
10e2 − 8
175e4.....
] [1 +
3
8
{1− 2
5e2 − 17
175e4...
}R
+ O(R2)]
= 1− 1
10e2 − 8
175e4 +
3
8
{1 +
3
10e2 − 1l8
175e4......
}R+O(R2),
(4.5)
where R = ρUa/µ, is particle Reynolds number. The same solution may bere-written, when we take particle Reynolds number R = ρUb/µ, by usingb/a = (1− e2)1/2, as
F
Fy= K
F
Fx
= K
1 + e3√1− e2
[−2e + (1 + e2) ln1+e
1−e
]R+O(R2
) ,
=
[1− 1
10e2 − 8
175e4.....
]1 + e3√1− e2
[−2e + (1 + e2) ln1+e
1−e
]R+O(R2)
]=
[1− 1
10e2 − 8
175e4.....
] [1 +
3
8
{1 +
1
10e2 +
109
1400e4......
}R
+O(R2)
]= 1− 1
10e2 − 8
175e4 +
3
8
{1 +
31
1400e4}R+O
(R2
).
(4.6)
Equations (4.5) and (4.6) immediately reduce to the case of sphere(given in(4.3)) in the limiting case as e → 0. On the other hand, the expressions (4.5)and (4.6) due to Oseen for prolate spheroid appear to be new as no such typeof expressions are available in the literature for comparison.
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...187
4.3 Flow past oblate spheroid
Stokes drag on oblate spheroid having semi-major axis length ‘b’ and semi-minor axis length ‘a’ placed in uniform velocity U, parallel to axis of symme-try(axial flow) and perpendicular to its axis of symmetry(transverse flow) isgiven as [by utilizing DS conjecture 2.4 and 2.5, Datta and Srivastava, 1999]
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 5: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUa/µ for oblate spheroid
Fx = 8πµUae3[e√
1− e2 −(1− 2e2
)sin−1e
]−1, (4.7a)
Fy = 16πµUae3[−e
√1− e2 +
(1 + 2e2
)sin−1e
]−1. (4.7b)
188 Deepak Kumar Srivastava & Nirmal Srivastava
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.80
10
20
30
40
50
60
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 6: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUb/µ for oblate spheroid
By using (4.7a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
Fy
=1
2
[−e
√1− e2 +
(1 + 2e2
)sin−1e
] [e√
1− e2
−(1− 2e2
)sin−1e
]−1= 1− 7
30e2 − 199
33600e4...
(4.8)
Now, from Brenner’s formula (2.8) and (2.9), the Oseen’s correction, with the
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...189
use of real factor K(cf. (4.8)), may be written as
F
Fy= K
F
Fx
=
[1− 7
30e2 − 199
33600e4.....
] [1 +
3
8
{1− 1
10e2 − 31
1400e4.....
}R
+O(R2)
]= 1− 7
30e2 − 199
33600e4 +
3
8
{1− 1
3e2 − 53
11200e4......
}R+O
(R2
),
(4.9)
where R =(ρUaµ
)is particle Reynolds number. The same solution may be
re-written, when we take particle Reynolds number R =(ρUbµ
), by using
b/a = (1− e2)1/2, as
F
Fy= K
F
Fx
= K
1 + e3
2√1− e2
[e√1− e2 − (1− 2e2) sin−1e
]R+O(R2
)=
[1− 7
30e2 − 199
33600e4...
] [1
+e3
2√1− e2
[e√1− e2 − (1− 2e2) sin−1e
]R+O(R2
)=
[1− 7
30e2 − 199
33600e4.....
] [1 +
3
8
{1
+2
5e2 +
61
200e4...
}R+O
(R2
) ]= 1− 7
30e2 − 199
33600e4 +
3
8
{1− 1
3e2 − 4079
33600e4......
}R
+O(R2
).
(4.10)
Equations (4.9) and (4.10) immediately reduces to the case of sphere(given ineq. 4.3) in the limiting case as e → 0. On the other hand, the expressions (4.9)and (4.10) due to Oseen for oblate spheroid appears to be new as no such typeof expressions are available in the literature for comparison.
190 Deepak Kumar Srivastava & Nirmal Srivastava
4.4 Flow past deformed sphere
We consider the polar equation of deformed sphere as
r = a
[1 + ε
∞∑k=0
dkPk (µ)
], µ = cosθ (4.11)
where ‘ε’ is deformation parameter and (r, θ) are polar coordinates. The Stokesdrag experienced by this deformed sphere placed in axial and transverse uni-form stream is given by use of by D-S formulae 2.4 and 2.5( Datta and Srivas-tava, 1999) only up to first order of ‘ε’ as
Fx = 6πµUa
[1 + ε
(d0 −
1
5d2
)], (4.12a)
Fy = 6πµUa
[1 + ε
(d0 −
1
10d2
)](4.12b)
By using (4.12a,b) and (2.7), the value of real factor ‘K’ comes out to be
0 0.2 0.4 0.6 0.8 10
10
20
30
40
50
60
Ose
en c
orre
ctio
n F
/F0
deformation parameter ε
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 7: Variation of Oseen correction with respect to deformation parameter‘ε’ for various values of Reynolds number R = ρUa/µ for deformed sphere
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...191
K =Fx
Fy
=
[1 + ε
(d0 −
1
5d2
)][1 + ε
(d0 −
1
10d2
)]−1
=
[1 + ε
(d0 −
1
5d2
)][1− ε
(d0 −
1
10d2
)]= 1− 1
10d2ε+O
(ε2).
(4.13)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor K(eq. 4.13), may be written as
F
Fy= K
F
Fx
=
[1− 1
10d2ε+O
(ε2)] [
1 +3
8
{1 + ε
(d0 −
1
5d2
)+O(ε2)
}R+O(R2)
]= 1− d2
10ε+
3
8
{1−
(d0 +
3
10d2
)ε
}R+O(R2),
(4.14)
where R =(ρUaµ
)is particle Reynolds number. This expression (4.14) imme-
diately reduces to the case of sphere (given in (4.2)) in the limiting case asε → 0. This further reduces to 1 for R = 0 (case of Stokes drag in transverseflow).
4.5 Cycloidal body of revolution
Case 1. We consider the equation of cycloidal body of revolution as
x = a (t + sint) , y = a (1 + cost) , − π ≤ t ≤ π (4.15)
The Stokes drag experienced by this cycloidal body of revolution placed inaxial and transverse uniform stream is given by use of DS conjecture 2.4 and2.5, [Datta and Srivastava, 1999]
Fx =128
3µUa, (4.16a)
Fy =256
5µUa. (4.16b)
192 Deepak Kumar Srivastava & Nirmal Srivastava
0 20 40 60 80 1000
10
20
30
40
50
60
70
80
90
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 8: Variation of Oseen correction with respect to Reynolds number R =ρUaπ/µ for cycloidal body
By using (4.16a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y=
5
6∼= 0.83. (4.17)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factorK(eq. 4.18), may be written as
F
Fy= K
F
Fx
=5
6
[1 +
8
3πR+O(R2)
]=
[5
6+
20
9πR+O(R2)
]∼= 0.8333 + 0.7077× R+O(R2),
(4.18)
where R = ρUa/µ, is particle Reynolds number. This expression reduces to0.8333 as R → 0, the case of Stokes drag i.e., F = 0.8333Fy which shouldbe equal to Fy. The reason behind this discrepancy is due to the error of
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...193
16.67 % which persists in the operation of D-S conjecture on cycloidal body ofrevolution (4.16).
0 20 40 60 80 1000
20
40
60
80
100
120
140
160
180
200
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 9: Variation of Oseen correction with respect to Reynolds number R =2aρU/µ for cycloidal body
Case 2. Consider the body generated by the rotation about x-axis of thecurve composed of arcs of two cycloidal parts represented parametrically by
x = a (1 + cost) , y = a (t + sint) , 0 ≤ t ≤ π (4.19a)
x = −a (1 + cost) , y = a (t + sint) , 0 ≤ t ≤ π. (4.19b)
The Stokes drag experienced by this cycloidal body of revolution placed inaxial and transverse uniform stream is given by use of by DS conjecture 2.4and 2.5, [Datta and Srivastava, 1999]
Fx =96π3
3π2 + 16µUa, (4.20a)
Fy =192π3
9π2 + 32µUa. (4.20b)
194 Deepak Kumar Srivastava & Nirmal Srivastava
By using (4.20 a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y=
1
2
(9π2 + 32
3π2 + 16
)∼= 1.3244. (4.21)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor K(eq. 4.21), may be written as
F
Fy= K
F
Fx
=1
2
(9π2 + 32
3π2 + 16
)[1 +
6π2
(3π2 + 16)R+O
(R2
)]= 1.3244 + 1.718964199× R+O
(R2
),
(4.22)
where R = ρUa/µ, is particle Reynolds number. This expression reduces to1.3244 as R → 0, the case of Stokes drag i.e., F = 1.3244Fy which shouldbe equal to Fy. The reason behind this discrepancy is due to the error of32.44 % which persists in the operation of D-S conjecture on cycloidal body ofrevolution (4.20a,b).
4.6 Egg-shaped body
We consider the egg-shaped body of revolution in which right portion is in theshape of semi spheroid obtained from revolution of ellipse
x = acost, y = bsint, 0 ≤ t ≤ π/2 (4.23a)
and left portion is in the shape of semi-sphere obtained from revolution of circle
x = bcost, y = bsint, π/2 ≤ t ≤ π, (4.23b)
about the axis of symmetry(x-axis). The Stokes drag experienced by thisaxially symmetric egg-shaped body in axial and transverse uniform stream isgiven by use of DS conjecture 2.4 and 2.5(see Datta and Srivastava, 1999)
Fx = 8πµUa
[2
3+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
, (4.24a)
Fy = 16πµUa√
1− e2
[4
3+
√1− e2
4e3
{2e +
(3e2 − 1
)ln1 + e
1− e
}]−1
. (4.24b)
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...195
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
10
20
30
40
50
60
70
80
90
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 10: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUa/µ for egg–shaped body
By using (4.23a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y
=1
2√1− e2
[4
3+
√1− e2
4e3
{2e +
(3e2 − 1
)ln1 + e
1− e
}][2
3(4.25a)
+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
= 1 +5
12e2 +
733
1680e4 + ... (4.25b)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor
196 Deepak Kumar Srivastava & Nirmal Srivastava
K(eq. 4.25), may be written as
F
Fy= K
F
Fx
=1
2√1− e2
[4
3+
√1− e2
4e3
{2e +
(3e2 − 1
)ln1 + e
1− e
}][2
3
+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
×
1 +1
2
[2
3+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
R+O(R2
)=
[1 +
5
12e2 +
733
1680e4....
] [1 +
3
8
{1 +
1
20e2 +
51
1400e4....
}R+O
(R2
)]=
(1 +
5
12e2 +
733
1680e4...
)+
3
8
{1 +
7
15e2 +
14511
29400e4 + ...
}R+O
(R2
),
(4.26)
where R = ρUa/µ, is particle Reynolds number. The same solution maybe written, when we take particle Reynolds number R = ρUb/µ, by usingb/a = (1− e2)
1/2, as
F
Fy= K
F
Fx
=1
2√1− e2
[4
3+
√1− e2
4e3
{2e +
(3e2 − 1
)ln1 + e
1− e
}][2
3
+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
×
1 +1
2√1− e2
[2
3+
√1− e2
4e3
{−2e +
(1 + e2
)ln1 + e
1− e
}]−1
R+O(R2
)=
[1 +
5
12e2 +
733
1680e4....
] [1 +
3
8
{1 +
11
20e2 +
611
1400e4....
}R+O
(R2
)]=
(1 +
5
12e2 +
733
1680e4 + ...
)+
3
8
{1 +
29
30e2 +
26271
29400e4 + ...
}R+O
(R2
).
(4.27)
These expressions (4.27) and (4.28) reduce to 1+ (3/8)R as e → 0, the case of
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...197
Oseen’s correction in transverse flow for sphere having radius ‘a’ which furtherreduces to 1 as R → 0, the case of transverse Stokes drag over egg-shapedaxially symmetric body.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
20
40
60
80
100
120
Ose
en c
orre
ctio
n F
/F0
eccentricity e
R=0 R=1 R=5 R=10 R=20 R=40 R=60 R=80 R=100
Figure 11: Variation of Oseen correction with respect to eccentricity ‘e’ forvarious values of Reynolds number R = ρUb/µ for egg–shaped body
4.7 Cassini body of revolution
We consider the cassini body of revolution obtained by revolving the curve
y2 =2
3
(1 + 3x2
)1/2 − x2 − 1
3, 0 ≤ x ≤ 1, (4.28)
about x-axis. The Stokes drag experienced by this axially symmetric cassinibody of revolution placed in axial and transverse uniform stream is given byDS conjecture 2.4 and 2.5 (see Srivastava, 2001), on taking a = 1, b = 0.577,is
Fx∼= 0.8πµU, (4.29a)
Fy∼= 0.82πµU. (4.29b)
198 Deepak Kumar Srivastava & Nirmal Srivastava
By using (4.30 a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y
∼= 0.9756098. (4.30)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor K(eq. 4.30), may be written as
F
Fy= K
F
Fx
∼= 0.9756098[1 + 0.3R +O
(R2
)]= 0.97561 + 0.2926829× R+O
(R2
)∼= 1 + 0.3R +O
(R2
),
(4.31)
where R = ρUa/µ is particle Reynolds number. This expression reduces to1 as R → 0, the case of transverse Stokes drag on cassini body of revolution(Srivastava, 2001).
0 20 40 60 80 1000
5
10
15
20
25
30
35
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 12: Variation of Oseen correction with respect to Reynolds numberR = ρU/µ for cassini body
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...199
4.8 Hypocycloidal body of revolution
We consider the hypocycloidal body of revolution obtained by revolving thecurve
y2 = −3x2 +√
(1 + 8x4), 0 ≤ x ≤ 1, (4.32)
about x-axis. The Stokes drag experienced by this axially symmetric hypocy-cloidal body of revolution placed in axial and transverse uniform stream isgiven by DS conjecture 2.4 and 2.5(see Srivastava, 2001), on taking a = 1, is
Fx∼= 6.264πµU, (4.33a)
Fy∼= 7.92πµU. (4.33b)
By using (4.34 a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y
∼= 0.7909091. (4.34)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor K(eq. 4.34), may be written as
F
Fy= K
F
Fx
∼= 0.8[1 + 0.3915R +O
(R2
)]= 0.8 + 0.31× R+O
(R2
),
(4.35)
where R = ρUa/µ is particle Reynolds number. This expression reduces to 0.8as R → 0, which should be 1, the case of transverse Stokes drag on hypocy-cloidal body of revolution (Srivastava, 2001). The reason behind this discrep-ancy is due to the error of 20% which persists in the operation of D-S formulaeon hypocycloidal body of revolution (4.32).
200 Deepak Kumar Srivastava & Nirmal Srivastava
0 20 40 60 80 1000
5
10
15
20
25
30
35
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 13: Variation of Oseen correction with respect to Reynolds numberR = ρU/µ for hypocycloidal body
4.9 Cylindrical capsule or shell
We consider the cylindrical capsule having semi-spherical caps on both endshaving same radius ‘b’ obtained by revolving the curves( PA, the circular seg-ment, AA’ , the line segment, A’P’ , again circular segment)
PA, x = b cos t, y = b sin t, 0 ≤ t ≤ π/2, (4.36a)
AA′, y = b, θ = π/2, (4.36b)
A′P ′, x = b cos t, y = b sin t, π/2 ≤ t ≤ π. (4.36c)
The Stokes drag experienced by this axially symmetric cylindrical body of rev-olution placed in axial and transverse uniform stream is given by DS conjecture2.4 and 2.5 (see Srivastava, 2001), is
Fx = 6πµUa, (4.37a)
Fy = 6πµUa. (4.37b)
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...201
By using (4.38a,b) and (2.7), the value of real factor ‘K’ comes out to be
K =Fx
F y= 1. (4.38)
Now, from Brenner’s formula (2.8) for axial flow and revised Brenner’s formula(2.9) for transverse flow, the Oseen’s correction, with the use of real factor K(eq. 4.34), may be written as
F
Fy= K
F
Fx
= 1
[1 +
3
16R +O
(R2
)]= 1 + 0.1875R +O
(R2
),
(4.39)
where R = ρU(2a)/µ is particle Reynolds number. This expression reduces to1 as R → 0, the case of transverse Stokes drag on cylindrical shell of revolution(Srivastava, 2001).
0 20 40 60 80 1000
5
10
15
20
25
Ose
en c
orre
ctio
n F
/F0
Reynolds number R
Figure 14: Variation of Oseen correction with respect to Reynolds numberR = 2aρU/µ for cylindrical capsule
202 Deepak Kumar Srivastava & Nirmal Srivastava
5 Numerical discussion
The numerical values of Oseen correction for various axi-symmetric bodies arecalculated for finite Reynolds number and presented in tables 1 to 13. For
Table 1: Numerical values of F/Fy with respect to Reynolds number (R =ρUa/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100 ) for sphere [calculated from eq.(4.3) anddepicted in figure 2]
Table 2: Numerical values of F/Fy with respect to eccentricity ‘e’ of prolatespheroid (0 ≤ e ≤ 1) for various values of Reynolds number (R = ρUa/µ =0, 1, 5, 10, 20, 40, 60, 80, 100) [calculated from eq.(4.5) and depicted in figure 3]
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...203
sphere, from table 1, it is clear that non-dimensional drag value F/Fy increasesfrom 1 to 38.50 with respect to increment in Reynolds number R from 0 (caseof Stokes drag) to 100. This variation is depicted by straight line in figure2. Similar behaviour of F/Fy persists for cycloidal body (both cases), cassinibody, hypocycloidal body and cylindrical capsule whose values are given inthe related tables (11,12,13) while their variations are depicted in the figures12,13,14. For prolate spheroid, in both situations when R = ρUa/µ and ρUb/µ,non-dimensional drag value F/Fy decreases slowly for low Reynolds number
Table 3: Numerical values of F/Fy with respect to eccentricity ‘e’ of prolatespheroid (0 ≤ e ≤ 1) for various values of Reynolds number(R = ρUb/µ =0, 1, 5, 10, 20, 40, 60, 80, 100) [calculated from eq.(4.6) and depicted in figure 4]
Table 4: Numerical values of F/Fy with respect to eccentricity ‘e’ of oblatespheroid(0 ≤ e ≤ 1) for various values of Reynolds number(R = ϱUa/µ =0, 1, 5, 10, 20, 40, 60, 80, 100,) [calculated from eq.(4.9) and depicted in figure 5]
(0 ≤ R ≤ 1) and increases slowly with respect to eccentricity ‘e’ (from 0 to 1.0)for Reynolds number beyond 5 whose values are given in tables 2-3 and corre-sponding variations are depicted in figures 3-4. Contrary to this fact, for oblatespheroid, in both situations when R = ρUa/µ and ρUb/µ, non-dimensionaldrag value F/Fy decreases slowly with respect to eccentricity ‘e’(from 0 to 1.0)for various specific values of finite Reynolds number 0 (case of Stokes drag)to 100 whose values are given in tables 4-5 and corresponding variations aredepicted in figures 5-6. It is interesting to note that for specific value of ec-centricity ‘e’, non-dimensional drag value F/Fy increases with respect to finiteincrement in R from 0 (Stokes drag) to 100. For design factors d0 = 0.5,
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...205
Table 5: Numerical values of F/Fy with respect to eccentricity ’e’ of oblatespheroid(0 e 1) for various values of Reynolds number(R = ϱUb/µ =0, 1, 5, 10, 20, 40, 60, 80, 100,) [calculated from eq.(4.10) and depicted in figure6]
d2 = 0.5, from table 7, it is clear that non-dimensional drag value F/Fy fordeformed sphere decreases with respect to deformation parameter ‘ε’ for variousvalues of increment in Reynolds number R from 0 (case of Stokes drag) to 100.This variation is depicted by straight lines in figure 7. For egg-shaped body,in both situations when R = ρUa/µ and ρUb/µ, non-dimensional drag valueF/Fy increases with respect to eccentricity ‘e’(from 0 to 1.0) for various specificvalues of finite Reynolds number 0 (case of Stokes drag) to 100 whose valuesare given in tables 7-8 and corresponding variations are depicted in figures11-10. It is interesting to note that for specific value of eccentricity ‘e’, non-dimensional drag value slowly increases with respect to finite increment in Rfrom 0 (case of Stokes drag) to 100.
206 Deepak Kumar Srivastava & Nirmal Srivastava
Table 6: Numerical values of F/Fy with respect to deformation parameter ‘ε’of deformed sphere (0 ≤ ε ≤ 1) for various values of Reynolds number(R =ϱUa/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) [calculated from eq.(4.15) for d0=d2=1and depicted in figure7]
In the present problem, we have extended the Brenner’s formulae(Brenner,1961), which were valid only for axial flow to transverse flow. This general ex-pression is used to correct the Stokes drag, called Oseen’s correction or Oseen’sdrag, up to the first order of Reynolds number ‘R’. This proposed solution isthe solution of Oseen’s equation. The numerical values of non-dimensionaldrag F/Fy with respect to various parameters like eccentricity ‘e’, deformationparameter ‘ε’ and Reynolds number ‘R’ related to axially symmetric bodiesare calculated and presented in tables 1-13. The respective variations betweenthese quantities are shown in figures 2-14. It has been observed that for low
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...207
Table 7: Numerical values of F/Fy with respect to eccentricity ‘e’ of egg-shaped body (0 ≤ e ≤ 1) for various values of Reynolds number(R = ρUa/µ =0, 1, 5, 10, 20, 40, 60, 80, 100) [calculated from eq.(4.26) and depicted in figure10]
particle Reynolds number(between 0 and 1), non-dimensional drag value de-creases and increases for other values of Reynolds number. The incrementin drag value is related to the increment in Reynolds number. The proposedanalysis may provide a strong platform to study the optimal profiles in Oseen’sflow which may appear in author’s future work. Other important applicationsof Oseen’s correction are in calculation of the settling of solid particles of pow-dered materials with enhanced accuracy in carrying out sedimentation analysisand in acoustic levitation. These two works are the main practical applicationsof Oseen’s correction which was not possible with the Stokes drag.
208 Deepak Kumar Srivastava & Nirmal Srivastava
Table 8: Numerical values of F/Fy with respect to eccentricity ‘e’ of egg-shaped body (0 ≤ e ≤ 1) for various values of Reynolds number(R = ρUb/µ =0, 1, 5, 10, 20, 40, 60, 80, 100) [calculated from eq.(4.27) and depicted in figure11]
Table 9: Numerical values of F/Fy with respect to various values of Reynoldsnumber(R = ρUaπ/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) for cycloidal body(case 1)[calculated from eq.(4.19) and depicted in figure 8]
Oseen’s correction to Stokes drag on axially symmetric arbitrary particle...209
Table 10: Numerical values of F/Fy with respect to various values of Reynoldsnumber(R = 2ρUa/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) for cycloidal body(case 2)[calculated from eq.(4.23) and depicted in figure 9]
Table 11: Numerical values of F/Fy with respect to various values of Reynoldsnumber(R = ρU/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) for cassini body of revolution[calculated from eq.(4.31) and depicted in figure 12]
Oseen correction ‘F/Fy’
R=0 R=1.0 R=5.0 R=10.0 R=20 R=40 R=60 R=80 R=100
1.0 1.3 2.5 4.0 7.0 13.0 19.0 25.0 31.0
Table 12: Numerical values of F/Fy with respect to various values of Reynoldsnumber(R = ρU/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) for hypocycloidal body ofrevolution [calculated from eq.(4.35) and depicted in figure 13]
Oseen correction ‘F/Fy’
R=0 R=1.0 R=5.0 R=10.0 R=20 R=40 R=60 R=80 R=100
0.80 1.11 2.35 3.90 7.00 13.20 19.40 25.60 31.80
210 Deepak Kumar Srivastava & Nirmal Srivastava
Table 13: Numerical values of F/Fy with respect to various values of Reynoldsnumber(R = 2ρUa/µ = 0, 1, 5, 10, 20, 40, 60, 80, 100) for cylindrical capsule[calculated from eq.(4.39) and depicted in figure 14]
First author convey his sincere thanks to University Grants Commission, NewDelhi, India, for providing financial assistance under major research projectscheme [F.N. 39-55/2010(SR), 24-12-2010] at the department of mathemat-ics, B.S.N.V. Post Graduate College, Lucknow(U.P.), India. Authors are alsothankful to the authorities of B.S.N.V. Post Graduate College, Lucknow, toprovide basic infrastructure facilities during the preparation of the paper.
References
[1] Brenner, Howard(1961) The Oseen resistance of a particle of arbitrary shape, J.Fluid Mech., vol. 11, pp. 604-610.
[2] Chang, I.D.(1960) Stokes flow of a conducting fluid past an axially symmetricbody in the presence of a uniform magnetic field, J. Fluid Mech., vol. 9, p. 473.
[3] Chester, W.(1962) On Oseen’s approximation, J. Fluid Mech., vol. 13, pp. 557-569.
[4] Datta, S. and Srivastava, D.K.(1999) Stokes drag on axially symmetric bodies: anew approach, Proc. Indian Acad. Sci.(Math. Sci.), vol. 109, no. 4, pp. 441-452.
[5] Dyer, Thomas W. and Ohkawa, Tihiro(1992) Acoustic levitation by Oseen drag,J. Acoust. Soc. Am., vol. 92, no. 4, pp. 2207-2211.
[6] Fung, Yuan-cheng(1997) Biomechanics: Circulation. 2nd ed. New York, NY:Springer-Verlag.
[7] Happel, J. and Brenner, H.(1964) Low Reynolds Number Hydrodynamics, Ni-jhoff, Dordrecht, The Nederlands.
[8] Kaplun, S.(1957) Low Reynolds number flow past a circular cylinder, J. Math.Mech., vol. 6, pp. 595-603.
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[9] Kaplun, S. and Lagerstrom, P.A.(1957) Asymptotic expansions of Navier-Stokessolution for small Reynolds numbers, J. Math. Mech., vol. 6, pp. 585-593.
[10] Krasovitskaya, R.A; Ermolaev, M.I.; Mukhin, A.A. and Mil’shenko, R.S.(1970)Use of Oseen’s correction in sedimentation analysis of powders, Chemistry andMaterials Science(Refractories and Industrial Ceramics), vol. 11, no. 7-8, pp.518-520.
[11] Lagerstrom, P.A. and Cole, J.D.(1955) Examples illustrating expansion proce-dures for the Navier-Stokes equations, J. Rat. Mech. Anal., vol. 4, pp. 817-882.
[12] Oseen, C.W.(1927) Neuere Methoden und Ergebnisse in der Hydrodynamik.Leipzig: Akademische Verlagsgesellschaft.
[13] Proudman, I. and Pearson, J.R.A.(1957) Expansions at small Reynolds numbersfor the flow past a sphere and a circular cylinder, J. Fluid Mech., vol. 2, pp.237-262.
[14] Srivastava, D. K.(2001) A note on Stokes drag on axi-symmetric bodies: a newapproach, The Nepali Mathematical Science Report, vol. 19, no. 1 and 2, pp.29-34.
[15] Srivastava, D. K.; Yadav, R.R. and Yadav, Supriya(2012) Steady Stokes flowaround deformed sphere: class of oblate bodies, Int. J. of Appl. Math. and Mech.,vol. 8, no. 9, pp. 17-53.
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[17] Stokes, G.G.(1851) On the effect of the internal friction of fluids on the motionof pendulums, Trans. Camb. Phil. Soc., vol. 9, pp. 182-187.
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Submitted in February 2014, revised in November 2014
212 Deepak Kumar Srivastava & Nirmal Srivastava
Oseen-ova ispravka Stokes-ovog otpora na osno simetricnojproizvoljnoj cestici u poprecnom toku: novi pristup
Dobijena je Oseen-ova korekcija Stokes-ovog otpora uslovljenog aksijalnosimetricnom cesticom postavljenom u uniformnu struju upravnu na osusimetrije (znazci poprecno tecenje). U tom cilju je iskoris cen linearni odnosizmedju uzduznog i poprecnog Stokes-og otpora za prosirenje Brenner-oveformule sa uzduznog na poprecno tecenje. Za opsti izraz Oseen-ova korek-cija Stokes-ovog otpora na uzduzno simetricnu cesticu postavljenu u poprecnotecenje nadjeno je da je nova. Ovaj opsti izraz primenjuje se na neka poznatauzduzno simetricna tela pa su dobijene vrednosti Oseen-ovog otpora, zakljucnosa prvim clanovima reda po Reynolds-ovom broju, takodje nove i ne postojeu literaturi. Numericke vrednosti Oseen-ovog otpora su takodje odredjene injihove promene u odnosu na Reynolds-ov broj, ekscentricitet i deformacioniparametar su prikazane i uporedjene sa nekim poznatim vrednostima. Nekevazne primene su takodje istaknute.