Learning Forum

[c2087845]

I am trying to run simulations for lift and drag at different angles of attack for an aerofoil. When inputting the lift force coefficients I enter a negative number, this causes an error saying "floating point exception". However I have checked and these values are supposed to be negative. I am using the student edition so im not sure if this is a limitation of that but any help is much appreciated

[Rob]

Where are you entering a negative number? 

[c2087845]

When i enter the x component of lift, the value is negative at the angle of attack I am using

[c2087845]

for some reason it works for my initial setup and solution on fluent but not for the duplicates I am creating for different angles of attack

[Rob]

How are you adding the lift component, or do you mean the vector definition? Pictures will help. 

[c2087845]

yes i mean the vector

[Rob]

That shouldn't have any effect on the solver stability, it's just to report the force components. 

If the model is failing, check the mesh and boundary settings are suitable: the NACA airfoil has been used as a tutorial/help video in Fluent and also in the Learning content on here. 

[c2087845]

is there a way to quikcly fix the sharp trailing edge in my aerofoil geometry as I believe this may be an isse

[Rob]

There are a couple of approaches. Trim the end to give a "blunt" trailing edge or break the geometry to extend the mesh from the trailing edge through the domain.