Developing CFD Teaching Laboratories Using ANSYS 1 Timur Dogan*, Michael Conger, Maysam Mousaviraad, Frederick Stern** IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, IA 52242 *
Graduate student seeking Ph.D. in Mechanical Engineering,
[email protected], (319) 621-9626
**
Advisor,
[email protected], (319) 335-5215
Abstract Computational fluid dynamics (CFD) is a widely used tool in fluids engineering, consisting of many commercial codes in use throughout the world. CFD is also a powerful tool used in the classroom to explain complex phenomena. A customized educational approach is developed to teach CFD to undergraduate and graduate students using the ANSYS Workbench interface while reinforcing introductory/intermediate fluid mechanics concepts. This approach and a series of teaching modules form the foundation of CFD laboratories for two courses at the University of Iowa: Mechanics of Fluids and Transport Processes and Intermediate Mechanics of Fluids. The project builds on the previous work on developing a hands-on integrated CFD educational interface [1-3]. The new teaching modules replace the previous streamlined educational interface software, FlowLab, allowing students to learn additional skills such as manual grid generation and manual verification and validation (V&V) using a commercial software. The work is done in collaboration with ANSYS Academic Program. The objective of the CFD labs is to teach students to perform complex CFD simulations for practical engineering applications without learning computer programming. The approach is developing a unique module that teaches students systematic CFD modeling, numerical methods and procedures in a hands-on, user-friendly, interactive manner. The educational approach for ANSYS Fluent automates the CFD simulation process, leading students step-by-step through setup and solution of a range of realistic engineering problems. The simulation process is: geometry, boundary definition, physics, mesh specification, solution procedure, reporting and post-processing. The process automation eases students from an introductory level of knowledge to the kind of expert knowledge of ANSYS Fluent they will need as practicing engineers after graduation. The practical engineering problems include: Verification of Laminar and Validation of Turbulent Pipe Flows, Verification and Validation of Turbulent Flow around a Clark-Y Airfoil, Simulation of Turbulent Flow in an Asymmetric Diffuser, and Simulation of Turbulent Flow over the Ahmed Body. Figure 1 shows an example of the simulation results. The educational approach was implemented in Fall 2013 semester. Undergraduate fluid mechanics labs were taught with the assistance of teaching assistance whereas the graduate fluid mechanics labs were completed by the students out of a laboratory setting. Figure 2 shows a photo of the undergraduate lab class. Prior to the labs, for both undergraduate and graduate level fluid mechanics courses, a CFD pretest was administered to students to determine a reference point in which to judge how effective the labs were in teaching fluids phenomena. A post test was administered after all the labs were completed and analysis was conducted on how effective the labs were in teaching the fluids phenomena. A post survey was conducted after the labs were completed in which the students evaluated the ANSYS Version 14.5 software and the lab manuals and their learning experience. 1
Abstract submitted to “Naval Engineers: The current fleet, the next class and the new prototypes”.
Fall 2013 evaluation results proved the approach very successful and popular with the students. The post-test scores showed 53% increase compared to the pre-test. The average post test scores for fall 2013 were comparable to previous years. The post-survey results are shown in Figure 3 and reflect high satisfaction with the students. The accumulative percent of “strongly agree”, moderately agree”, and “mildly agree” answers to the survey questions regarding the goal of the CFD labs, add up to 92% in Fall 2013, while 77% in Fall 2012 when FlowLab was used. The final paper will include the details of the four CFD labs designed for the graduate course; the undergraduate labs are simplified versions of the first two labs. The details of the CFD process and V&V objectives of each lab will be included. Also the implementation in Fall 2013 will be discussed in more detail including the statistical results and comparison with previous years and student feedbacks. Acknowledgments This work was done in collaboration with ANSYS Academic Program. The Naval Engineering Education Center (NEEC) provided partial support including student funding. References [1] Stern, F.; Yoon, H.; Yarbrough, D.; Okay, M.; Oztekin, U.; Roszelle, B. Hands-On Integrated CFD Educational Interface for Introductory Fluids Mechanics: Invited Paper. International Journal Aerodynamics, 2012, Vol. 2 Nos. 2/3/4, pp. 339 – 371. [2] Stern, F.; Xing, T.; Muste, M.; Yarbrough, D.; Rothmayer, A.; Rajagopalan, G.; Caughey, D.; Bhaskaran, R.; Smith. S.; Hutching, B.; Moeykens, S. Integration of Simulation Technology into Undergraduate Engineering Courses and Laboratories. International Journal Learning Technology, 2006, Vol. 2, No. 1, , pp. 28 – 48. [3] Stern, F.; Xing, T.; Yarbrough, D.; Rothmayer, A.; Rajagopalan, G.; Otta, S.P.; Caughey, D.; Bhaskaran, R.; Smith. S.; Hutching, B.; Moeykens, S., Hands-On CFD Educational Interface for Engineering Courses and Laboratories, Journal Engineering Education, 2006, Vol. 95, No. 1, , pp. 63 – 83.
Figure 1 unsteady simulation of turbulent flow over a generic slant-back car. The top figure shows the contours of turbulent viscosity ratio visualizing the wake flow, and the bottom figure shows the velocity vectors colored by axial velocity.
Figure 2 Undergraduate students with graduate student teaching assistant conducting CFD labs for Mechanics of Fluids and Transport Processes
Figure 3 Fall 2013 post-survey statistics for students answers for questions related to satisfaction with the CFD labs
