Exact Reimann Solver finished

I have finished the Exact Riemann Solver program and have tested it against Toro's and it works well. The code basically uses the different wave speeds in the grid to determine any position on the grid (x,t). This was a really neat concept. Using relative wave speeds, one can determine at which point in solution space you are, and thus the fluid variables at that point are given analytically. This is because there are essentially 5 possibilities - pre- or post- shock, ahead, behind, or within rarefaction fan. The waves spread out from the contact discontinuity - (although, not sure why this would be a strict condition from the equations) - and so the algorithm checks the relative pressures ahead and behind the waves to determine whether the wave is a shock or rarefaction. A shock has simple expressions for the post shock region, given by the jump conditions, and so the pre-shock region would just be the initial data state, and the post shock would be given by the jump condition. The post-shock region is aka "the star region" and its pressure and velocity are constant through-out. This region is where the initial discontinuity of the Reimann problem exists as well, later to travel through the grid as the contact discontinuity. What I am trying to get at is that behind any wave, the rho is given by either the jump condition or the isentropic condition for a rarefaction. This is a constant value until the contact is reached. Once the sampling point passes the contact, the same is true on the other side. So in this sense there are 4 regions - 1. Left state, 2. Left star region (with p, u given by the Reimann solver, and rho determined by the left state's post wave solution), 3. Right star state (same situation as 2, but with reference to right wave solution, 4. Right state.

Here is my progress page that links to my code and shows the results of the Toro tests: ​https://clover.pas.rochester.edu/trac/astrobear/wiki/u/erica/ExactRiemannSolver

The directory is here: grassdata/erica/ExactRiemannSolver

Comments

No comments.