To Go Supersonic, Widen the Pipe — The De Laval Nozzle and Choking
·6 min read
Area ratio 4 designs to Mach 2.940 and pe/p0 of 0.0298. Gamma 1.4 locks the choked mass-flow factor near 0.5787, and back pressure stays out of it.
Above Mach 1, You Must Widen to Speed Up — The Laval Nozzle Paradox
·7 min read
Area ratio 2.5 exits near Mach 2.44 on the supersonic branch, static pressure at 6.3 percent of stagnation. Raise back pressure and a shock stands inside.
Discontinuous Galerkin Method (DGM): High-Precision Discretization for Unstructured Grid Compressible Flow Analysis
·4 min read
In 3D the degrees of freedom at K = 1, 2, 3 are 4, 10, and 20. Halving the mesh spacing should cut the error by 4, 8, and 16, not by 2.
Mach Architect: Learn Compressible Flow by Designing Nozzles
·4 min read
At γ = 1.4 the choke ratio is 0.5283 and the M = 2 area ratio is about 1.6875. Back pressure between those two parks a normal shock inside the nozzle.
Compressible Multiphase Flow CFD: Why It's Hard, Why It Matters
·5 min read
Averaging gamma at a gas-liquid interface does not recover the pressure. Near half gas fraction, the mixture sound speed falls to about one hundredth.