University:
Boston University
Course:
CAS PY 105 | Physics 1
Academic year:

2020
Views:

447

Pages:

12
Author:

Byron Evans

Use wedge boundary conditions to take advantage of this symmetry. 11 Conditions used in the construction of the nozzle: Pressure slip 1 totalPressure 0 waveTransmissive z[m] 2 empty wedge 12 Conditions used in the construction of the nozzle: Temperature slip fixedValue 1 0 zeroGradient z[m] 2 empty wedge 13 Conditions used in the construction of the nozzle: Velocity slip zeroGradient 1 0 zeroGradient z[m] 2 empty wedge 14 The inlet and outlet boundaries are set with a pressure gradient Inlet: 1 Outlet: 0 z[m] 2 are set by the simulation and 15 Simulation uses the rhoCentralFoam solver Density-based compressible flow solver based on centralupwind schemes Uses Sutherland’s law to calculate the dynamic viscosity Assumed the flow was laminar (no turbulence) 16 Initially get waves and shocks that dissipate over time 17 Finally settle into a supersonic steady state flow 18 We can compare the simulation results to analytic inviscid solutions M T[K] Z [m] Z [m] 19 We can compare the simulation results to analytic inviscid solutions u [m/s] p[Pa] Z [m] Z [m] 20 Looking at residuals tells us if the simulation has converged 21 Summary • Nozzles can transition flow from subsonic to supersonic • Built a flexible Python code that generates meshes that have cylindrical symmetry • Using that mesh, set up a simulation of a supersonic de Laval nozzle that agrees with the analytic results quite well 22