Computation of Airfoil Boundary Layer - Engineering Assignment Help

Assignment Task

Introduction
The aims of the exercise are to
- Allow experience to be gained in setting up and running a flow computation with a commercial CFD package.
- Enable an exploration to be carried out on the effects and accuracy of different convection schemes and grid densities.
- To make comparisons between predictions using a simple turbulence model and experimental measurements.

The laboratory exercise allows one to use the Fluent software to compute the flow around a conventional airfoil model. The flow is 2-dimensional, and should be computed as both a low-Reynolds-number laminar case, and a high-Reynolds-number turbulent flow.
The flow domain being considered is a little smaller than one might choose in a real application (where one wants to ensure that the outer “free-stream” boundary conditions do not influence the flow). However, it is sufficient for the purposes of this exercise. A number of pre-defined grids are available, allowing one to examine the effects of different grid densities and discretization schemes. The grids are all ‘C’ type meshes: the coarsest grid to be used for the laminar flow calculations has 40 nodes wrapped around the airfoil and wake, and 10 from the airfoil to the outer boundary. The other grids have densities of 80x20, 160x40 and 320x80 nodes, each obtained by successively dividing each cell dimension by 2. For the turbulent flow calculation a single grid of 220x100 nodes is provided, with a much higher density of grid nodes close to the airfoil surface.
Although not required for this exercise, for those interested there is a document on Blackboard outlining how these grids can be built using ANSYS Workbench.

Investigations
Grid-Dependence and Accuracy of Discretization Schemes
For these investigations, a laminar flow should be computed at a Reynolds number of 275 (based on chord length and free-stream velocity).
The flow should be computed at an angle of incidence of 10o
This is set when defining the inlet boundary conditions.
Because of time constraints, it is suggested that only three grids are examined during the lab. The computed lift and drag coefficients from the finest grid are included for reference in the table below.
- A solution should be obtained on the coarsest grid using the first order upwind scheme for convection.
- Obtain a corresponding solution using the QUICK convection scheme on the coarsest grid. Note that it will usually be faster to start this calculation from the converged
1st order upwind scheme one, instead of re-initializing the solution; simply go to Solution Methods in the navigation tree, select the QUICK scheme, and then go to Run Calculation, without re-initializing the solution.
- Repeat the above calculations using first order upwind and QUICK schemes for the two medium grids.
- From the Cl and Cd results obtained, draw conclusions on the level of grid independence achieved using the two convection schemes on the different grids. Is the behaviour what one might expect from a first order and a third order discretization scheme as the grid is refined?
- For the upwind scheme results, use Richardson extrapolation from two of the grids to obtain higher order estimates for Cl and Cd. Do these estimates agree with
conclusions you may have drawn on the numerical accuracy of the results?
- From three of the upwind scheme results, use Richardson extrapolation formulae to estimate the order of accuracy of the scheme. Does it give a result close to 1st
order?

This Engineering Assignment has been solved by our Engineering experts at My Uni Papers. Our Assignment Writing Experts are efficient to provide a fresh solution to this question. We are serving more than 10000+ Students in Australia, UK & US by helping them to score HD in their academics. Our Experts are well trained to follow all marking rubrics & referencing style.