I analysed a plate in different wind tunnel then I am getting different value of Drag Force Fd & Coefficient of Drag for a verticle plate of 1 m^2 cross sectional area and 100 mm thickness while changing the wind tunnel size in project Falcon by autodesk (I attached photo of analysis with different wind tunnel size..take a look) How it is possible??
1. Wht should i do so that i can get correct result? 1. plz help me to decide optimal size of virtual wind tunnel in falcon so that i can get correct answer..
2. Wht is the volume stand for that i highlighted in the pics?? plz reply.. Thanks & Regards..
The area of the wind tunnel compared to the frontal area of the test article needs to be at least ten times larger to even approximate a correct simulation. Much better is as large and can be accomodated. The flow is restricted not just by the test article but also by the boundaries. For best results when test articles must be compared the ratio of frontal area to total tunnel cross sectional area should be similar.
When the test article is an appreciable part of the total area and asymmetrical then even just changing the orientation of the test article will change the ratio. That will alter the results and needs to be taken into account. This is true of a physical wind tunnel as well as a simulation. The great advantage of the simulation is that the flow velocity is arbitrary and may be kept constant regardless of tunnel area.