UFR 2-12 Test Case
Turbulent Flow Past Two-Body Configurations
Flows Around Bodies
Underlying Flow Regime 2-12
Test Case Study
Brief Description of the Study Test Case
- Convey the general set up of the test-case configuration( e.g. airflow over a bump on the floor of a wind tunnel)
- Describe the geometry, illustrated with a sketch
- Specify the flow parameters which define the flow regime (e.g. Reynolds number, Rayleigh number, angle of incidence etc.)
- Give the principal measured quantities (i.e. assessment quantities) by which the success or failure of CFD calculations are to be judged. These quantities should include global parameters but also the distributions of mean and turbulence quantities.
The description can be kept fairly short if a link can be made to a data base where details are given. For other cases a more detailed, fully self-contained description should be provided.
Test Case Experiments
Provide a brief description of the test facility, together with the measurement techniques used. Indicate what quantities were measured and where.
Discuss the quality of the data and the accuracy of the measurements. It is recognized that the depth and extent of this discussion is dependent upon the amount and quality of information provided in the source documents. However, it should seek to address:
- How close is the flow to the target/design flow (e.g. if the flow is supposed to be two-dimensional, how well is this condition satisfied)?
- Estimation of the accuracy of measured quantities arising from given measurement technique
- Checks on global conservation of physically conserved quantities, momentum, energy etc.
- Consistency in the measurements of different quantities.
Discuss how well conditions at boundaries of the flow such as inflow, outflow, walls, far fields, free surface are provided or could be reasonably estimated in order to facilitate CFD calculations
Provide an overview of the methods used to analyze the test case. This should describe the codes employed together with the turbulence/physical models examined; the models need not be described in detail if good references are available but the treatment used at the walls should explained. Comment on how well the boundary conditions used replicate the conditions in the test rig, e.g. inflow conditions based on measured data at the rig measurement station or reconstructed based on well-defined estimates and assumptions.
Discuss the quality and accuracy of the CFD calculations. As before, it is recognized that the depth and extent of this discussion is dependent upon the amount and quality of information provided in the source documents. However the following points should be addressed:
- What numerical procedures were used (discretisation scheme and solver)?
- What grid resolution was used? Were grid sensitivity studies carried out?
- Did any of the analyses check or demonstrate numerical accuracy?
- Were sensitivity tests carried out to explore the effect of uncertainties in boundary conditions?
- If separate calculations of the assessment parameters using the same physical model have been performed and reported, do they agree with one another?
Contributed by: A. Garbaruk, M. Shur and M. Strelets — '
© copyright ERCOFTAC 2020