Tennessee Technological University Tennessee Tech UNIVERSITY A Forensic Engineering Teaching Paradigm for Improving Student Learning of Hydraulics Faisal.

Tennessee Technological University

Tennessee TechUNIVERSITY

A Forensic Engineering Teaching Paradigm for Improving Student

Learning of Hydraulics

Faisal Hossain

Department of Civil and Environmental Engineering


ASEE-SE Conference 2009



Key words: Some Definitions

Forensic Engineering is the investigation of materials, products, structures or components that fail or do not operate/function as intended, causing personal injury or damage to property. – Wikipedia

Forensic - forensis”. Retracing/reconstructing the sequence of events leading to the current state (e.g. a crime)

‘


Faisal Hossain


Forensic Engineering = Reverse Engineering

Reverse engineering (RE) is the process of discovering the technological principles of a device, object or system through analysis of its structure, function and operation.

http://upload.wikimedia.org/wikipedia/commons/a/a0/ReverseEngineering_Silberpfeil_notext.png

Faisal Hossain


‘Reverse’ or ‘Forensic’ paradigms in Classroom for Engineering

Well-known to improve classroom learning in Mechanical/Industrial/Electrical Engineering courses

Protocols for Improving Learning using ‘Reverse’ engineering are well-established for these disciplines.

Prism Issue on Forensic Engineering in 2008.

For Civil Engineering design courses, Forensic paradigms are not as easy to implement. (We still haven’t figured out the Pyramids).

For example- Can you take a bridge apart to find out how it works as easily as a ‘car’? Can you find the compressive strength of a concrete cube without crushing it?



Forensic Engineering Paradigm in Hydraulics

Hydraulics – “Application of Fluid Mechanics for Design of Water-structures”

Teaching of Hydraulics is historically ‘forward’ – design objective is known; design procedure begins from basics using deductive reasoning (applying ‘formulas’ to a specific example).

Traditional teaching may not improve learning of Hydraulics beyond ‘Application’ (Bloom’s Taxonomy level 3)

Example of a Traditional ‘Forward’ Teaching Method: Culvert Design


• First, know your design Q (discharge).• Second, know the field conditions at culvert location.• Third, apply procedure (step-by-step iteration).

Step One Design culvert (D,So)

to pass flood of given return period (10 or 100-year event).

Design Q Rational method TR-55 method

drainagearea

road

culvert


Step 2: Field Conditions

datum

DH

road deck

headwater/inlet

outlet/tailwater

outlet invert El.intlet invert El.

h4

L, So

Ao=area of culvert barrel; A3=area of section of flow at outletlW=typ. one stream width

1 2

3

4

V1

lw

Qz


Step 3: Find ‘Type’ and Apply formulas

1. Estimate Qdesign for drainage area & design return period.2. Select culvert shape, material and trial size, D and calculate H/D.3. Design for desired culvert flow type & select discharge formula.

Unsubmerged flow conditions (e.g. box culverts supporting roadways)

a) Calculate dc & dn and classify slope as Mild or Steep

b) Compare dn, dc and tailwater depth h4 and classify flow type: dn <dc; h4<dc : S2 profile, inlet control with dc as control depth, TYPE 1

c) dn >dc; h4 <dc : M2 profile, outlet control with dc as control depth, TYPE 2

d) dn >dc; h4 >dc : M2 profile or M1(h4 > dn), outlet control with h4 as control depth, TYPE 3

4. Calculate Qtrial and compare with Qdesign. Iterate until they equal.

Forward Way of Teaching Hydraulics may not achieve higher learning


Step 1 – Step 2 – Step3

Deductive (applying formulas for a specific example)

Too well-defined.

Too structured.

Anyone can do it if the steps are memorized.

Is it really teaching students ‘Hydraulics?

Learning can be improved by going ‘Forensic’

A Forensic Paradigm of Teaching Hydraulics:


First teach the traditional forward way of design.

Teach all necessary theory and steps.

Next, provide students with a real-world structure and ask them to find the design capacity for which it is designed.

Do not provide any other information, but let them use any resource they want.

Tell students that they already know enough to ‘retrace/reconstruct’ the pieces and arrive at Design Q (a known in the forward method).

Encourage students to come up with ideas on ‘retracing’ the design steps. (e.g. - Giza Pyramid Analogy).

A Real-World Example of Forensic Teaching – Spring 2008 CEE3420


Find Design Q and Return Period for this Open Channel in Cookeville, (1 mile from classroom).

No other information is provided

Experience with Forensic Teaching


1. Students were far more creative in solving ‘reverse’ or ‘forensic’ problems due to lack of restraints and ‘open-ended’ nature of solution (no unique solution).

2. Students were forced to ‘think’ and work in groups.

3. Groups scoped the area with surveying instruments, took dimensions of the channel.

4. Students applied their ‘forward’ learning ‘backwards’, got stuck, aimed to overcome those (encouraged interaction with me on fundamental principles).

5. Many interesting ideas were observed that clearly demonstrate ‘thinking’ mind of the students to overcome real-world problems.

Experience with Forensic Teaching: Student Evaluation


“So to conclude, there are many benefits that come from the solutions of this problem that reach far past simply finding a numerical answer. In getting the experience of going out and taking real-world measurements in the field and then applying them to academic formulas, we got first hand experience that not everything is cut and dry and given so plainly as the ‘givens’ are in a typical problem. There is an abundance of gray area in hydraulics application due to assumptions that must be made on occasion……..While engineering is bound by the rigid constraints of mathematics and physics, we were able to discover the liberty of the logic and the discretion that comes with application. ….”

Conclusions


Traditional Hydraulics teaching is ‘forward’ where students are exposed to an overly-structured and well-defined teaching procedure.

Forward way of teaching hydraulic design may not extend learning beyond simple ‘application’. Questions arise on the true nature of learning of fundamental hydraulic principles for design.

Coupling Reverse or Forensic paradigm to the forward way using real-world hydraulic structures is found to be effective.

Forensic mode generates excitement among students

Forensic mode improves learning the inductive way.

Tennessee Technological University Tennessee Tech UNIVERSITY A Forensic Engineering Teaching Paradigm for Improving Student Learning of Hydraulics Faisal.

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