Hello, I'm trying to use the compressible flow solver in Nektar++ for a laminar supersonic compression ramp case. I'm using version 4.3.4. After running into issues and digging around in the code a bit, I figured out that the only Riemann solver which includes the viscous fluxes is HLLC. After switching the UpwindType to HLLC, the code runs, but it quits after the second time step. Here is the output of the code: ======================================================================= Initial Conditions: - Field rho: rhoInf - Field rhou: rhoInf * uInf - Field rhov: 0 - Field E: pInf / (Gamma - 1) + 0.5 * rhoInf * uInf * uInf - Field eps: 0 Writing: "ramp_0_0.chk" Steps: 1 Time: 1e-09 CPU Time: 0.922648s Writing: "ramp_0_1.chk" Steps: 2 Time: 2e-09 CPU Time: 0.866426s Fatal : Level 0 assertion violation NaN found during time integration. I tried different time integration schemes to see if that helped, to no avail. Any insights or pointers on what is causing the NaNs? A coarse mesh file and session file are attached. Thanks for your time, James