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 jayanth1990 August 21, 2012 11:49

help in external aerodynamics

hello people im new here and i just finished a basic cfx course but still im not well versed in it
i learned cfx because it will be useful for my project work in external vehicle aerodynamics

i ran into several problems while im trying to solve the model

1) in the place i learnt they thought me they tld me u have to subtract the solid model from the external domain in case of external aerodynamics then mesh it
but when i try to do subract in boolean operation ( in ansys modeller) it gives me errors when i try the body operation all the surfaces are not deleted

2)it is seen that if ur going to analyse a car at particular wind speed u need certain domain measurements were can i get those formulas ?

3)how am i going to calculate the frontal are of the car which is needed for the drag calculations

 singer1812 August 21, 2012 14:34

From your post, it seems like you are new to CAD and CFD. Try some simple things first.

1) Use a cube shape or sphere shape instead of your vehicle shape. Try subtracting that from the air domain. This will let you see how it works. You might have poor vehicle geometry which prohibites the operation.

2) Once again, use a cube or sphere first. Look up in any elementary text book. The equations for measurement are in there. Do something simple. Using a cube or sphere also allows you to quickly compare results to textbook examples.

3) Use a projected frontal area. CAD system will tell you this. Depeneds on what you are working in.

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