boundary condition for impulsive start
 

hi, I have developed a code for cartesian grid method. It gives good results for flow past circular cylinder. Now I want to simulate flow past an impulsively started airfoil. Can any one help me in specifying boundary condition for velocity for an impulsively started flow? Thanks for your advice

Re: boundary condition for impulsive start
 

You apply U=1, and V=0 as an Initial condition in the domain keep the boundary conditions as it is. Sachin

Re: boundary condition for impulsive start
 

hi sachin, thank you for your reply.. but by applying U=1 and V=0 how can we represent the impulsive motion? shouldn't the boundary condition be time dependent?

Re: boundary condition for impulsive start
 

Assuming a Galilean transformation, it doesn't really matter whether you start the fluid impulsively past a fixed boundary (Sachin's approach) or you impulsively start the body into a fixed fluid (your approach). Sachin's recommendation is easier.