Boundary layer transition problem
 

I am using DNS to study the boundary layer transition problem. I find in my model, the 3D structures like, lambda vortex, always come up at higher Reynolds number (and correspondingly the waves with higher spanwise wavenumber show weaker amplification), compared with other simulations and experiments.

I am solving 3D vorticity-velocity NS equation with finite difference in downstream and wall-normal directions and spectral method in spanwise direction.

I wonder if anyone has similar experience? What are the possible reasons that may lead to current results?

Thank you.

You need to be sure you use the same initial conditions for your simulation as your reference cases. DNS is very sensitive to small modifications of the initial conditions.

Do

Thank you so much Do.

Your suggestions inspire me. I measured my initial conditions in spectral space and did not notice the differences with experiments.