Direct numerical simulations (DNS)
We have
extended the influence-matrix method (Kleiser and Schumann, 1980) for
direct numerical simulations to account for the generalized boundary
conditions (Robin type). The paper detailing the new method has been
published by the Journal of Computational Physics. See the Publications section for details.
The main contributions outlined in the JCP paper:
You can download my version of the code here: channelflow_Uc.tgz.
The new method greatly extends the applicability of the influence-matrix method. The original method is only good for wall bounded channel flows. Here are some examples demonstrating the new method.
The main contributions outlined in the JCP paper:
- Generalized velocity boundary conditions for the streamwise and spanwise directions (Robin type)
- Wall normal direction velocity could also be arbitrary (no penetration, blowing/suction, etc.)
- It does not matter if steady or unsteady B.C.
- "Tau" correction algorithm to achieve high accuracy (up to
machine precision)
- Parallel computation (OpenMP). We have done simulations using upto 1024 cores in NCSA supercomputers.
- Boussinesq approximation for buoyancy. We used this code for
simulations of density/turbidity current.
You can download my version of the code here: channelflow_Uc.tgz.
The new method greatly extends the applicability of the influence-matrix method. The original method is only good for wall bounded channel flows. Here are some examples demonstrating the new method.
3D |
2D |
Mean
velocity profile |
R.M.S. |
Divergence of the velocity field |
Density current in wall-bounded and open channels (Gr=1.5E6)
- B.Cs: Open channel (Bottom: no slip Top: shear-free) Wall bounded (Bottom: no slip Top: no slip)
- Lock exchange type simulations
Reference: Liu and Jiang (2013), see Publications.
Open Channel |
Wall-bounded Channel |
Open Channel (spanwise averaged) |
Wall-bounded Channel (spanwise averaged) |
Open Channel (spanwise averaged, velocity vector) |
Wall-bounded Channel (spanwise averaged, velocity vector) |