Background Development of overset mesh CFD solver in OpenFOAM Preliminary results Conclusions & future work WP1: Multiphase modelling with overset mesh Zhihua Ma, Ling Qian, Derek Causon, Clive Mingham, and Pedro Martínez Ferrer Centre for Mathematical Modelling and Flow Analysis The Manchester Metropolitan University 2016-06-06 Ma, Qian, Causon, Mingham & Ferrer CMMFA – MMU 1/23
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WP1: Multiphase modelling with overset mesh · WP1: Multiphase modelling with overset mesh ZhihuaMa,LingQian,DerekCauson,CliveMingham, andPedroMartínezFerrer Centre for Mathematical
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BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
The overall strategyogFoam: a multiphase overset mesh modelling tool
Zonal approach for L and R
7
e of this research and following industrial partners’ suggestions, the new tool will
odel. However, the velocity potential needed for the QALE-FEM will velocity he multi-s zero in non-zero d so the ocity and on differ- region. ues will ored to ing be- in the
, QALE-e steps o max- e NS
NS
FNPT
Larger vessel
Smaller vessel
Inner domain
Outer domain
Meshes for larger and small vessels are generated independentlythen assembled together. The small mesh surrounding the smallvessel moves with the vessel (6DoF), the big mesh could move withthe large vessel or stay stationary.
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
The overall strategyogFoam: a multiphase overset mesh modelling tool
Basic steps of OGM
1 Mesh generation: component grids are generated in a(virtually) independent manner.
2 Domain connectivity information (DCI):Hole cutting: blank out the mesh cells out of flow domain.Locate the fringe points and seek interpolation stencils (onother meshes).Orphan point: a proper interpolation stencil cannot beestablished.
3 Flow information exchange: the information at a fringe pointis interpolated from its supporting stencil.
4 Solve the flow on the filed points/cells, update the flow.5 Repeat steps 2 to 4 for deforming/moving boundary problems.
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
The overall strategyogFoam: a multiphase overset mesh modelling tool
wsiFoam
A multi-region two-phase flow solver for wave-structureinteractions.
Coupling of incompressible and compressible two-phaseNavier-Stokes solvers.Coupling of single-phase potential flow and two-phase NSsolvers.Wave generation:
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
DambreakWave tankWedge
Dambreak-1
The red and green lines represent the free surface obtained onoverset meshes and a single-block mesh. The white lines illustratethe pressure contour lines on the two overset meshes.
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
DambreakWave tankWedge
Dambreak-2
Comparison of the overset mesh solution and the single-block-meshsolution. The red and green lines represent the free surfaceobtained on overset meshes and a single-block mesh.
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
DambreakWave tankWedge
Wave tank
Tank size: 320 m × 55 m; Water depth: 30 m; Wave height: 5 m.Wave Period: 10 s. Comparison of the overset mesh solution andthe single-block-mesh solution. Red and blue colours indicate thediscrepancy between the two solutions.
BackgroundDevelopment of overset mesh CFD solver in OpenFOAM
Preliminary resultsConclusions & future work
Conclusions
Conclusions
An accurate and fast modelling tool is a necessity to predictrisks and to facilitate testing for launch and recoveryoperations at high sea states.Dynamic deforming mesh method has limitations in dealingwith the large amplitude of structure motion and mesh quality.A multiphase overset mesh modelling tool is being developedwithin the framework of OpenFOAM. Preliminary results havebeen produced and presented for several test cases. The toolshows its advantages in dealing with relatively large amplitudeof structure motion.Next step’s work will focus on the improvement ofhole-cutting, information interpolation, parallelisation of thenumerical tool and further extension to handle L and Roperations.