NSCBC-Openfoam project

• Aim: Reproduce the Nonreflecting boundary condition in paper “Partially reflecting and non-reflecting boundary conditions for simulation of compressible viscous flow”
• Ref: see here
• New: 1. add backward NRBC scheme;
• Sponsor：Dong
• Acknowledge：Cheng

parameter

				const scalarField K(etaAc_*(1.0-sqr(aP/cP))*cP/lInf_);

• K:calculated relaxation constant
• etaAc_ $\approx$ 0.27 (to balance the dirft(etaAc<0.27) and non-reflect effectetaAc>0.27))
• lInf_: streamwise extent of the computational domain
• cP: calculated sound speed
• aP/cP: calculated Mach number

by G. Daviller

Test_cases:

01-sineWaveDamping-rhoPimpleFoam

Time scheme	Link	Info
Euler scheme explicit	sineWaveDamping01	Ref01
Backward Scheme	sineWaveDamping02	Ref02
Backward Scheme & p-sineWave & NRI-NSCBC	sineWaveDamping03	Ref03
Backward Scheme & p-sineWave & zeroGradient	sineWaveDamping04
Backward Scheme & U-sineWave & NRI-NSCBC	sineWaveDamping05
Backward Scheme & p-triWave & NRI-NSCBC	sineWaveDamping06
Backward Scheme & U-waveletWave & NRI-NSCBC	sineWaveDamping07
Backward Scheme & U-waveletWave & NRI-NSCBC	sineWaveDamping08	2e-6(case07) vs dt=2e-5 (case08)

02-sineWaveDamping-rhoPimpleFoam vs LusgsFoam

The LusgsFoam solver could be found: https://github.com/furstj/myFoam , plase refer it if use it.

Time scheme	Link	Info	Time
sineWaveDampingPimpleFoam-Euler	sineWaveDamping01	Timeseries01	4cores,142.55 s
sineWaveDampingPimpleFoam-backward	sineWaveDamping02	Timeseries02	4cores,153.13 s
sineWaveDampingLusgsFoam-Euler	sineWaveDamping03	Timeseries03	4cores,34.11 s
sineWaveDampingLusgsFoam-backward-iter10	sineWaveDamping04	Timeseries04	4cores,184s
sineWaveDampingLusgsFoam-backward-iter50	sineWaveDamping04	Timeseries04	4cores,283s
sineWaveDampingLusgsFoam-backward-iter100	sineWaveDamping04	Timeseries04	4cores,270s (converged)

03-ductWave 3D test - Mesh independent Test - waveTransimition boundary condition

CaseName	cells in Z-direction	Link	Info	Time
sineWaveDampingPimpleFoam3Dduct-basic	115	sineWave3D	too coarse mesh in z-direction, sinWave3D-plot-in-space	64 cores, 2028 s
sineWaveDampingPimpleFoam3Dduct-Z16	135	sinWave3D	no-converaged, timeSeries space	64cores, 2069 s
sineWaveDampingPimpleFoam3Dduct-Z32	270	sinWave3D	no-converaged, timeSeries space	64cores, 4582 s
sineWaveDampingPimpleFoam3Dduct-Z64	540	sinWave3D	converaged, timeSeries space	64cores, 10372 s

04 sineWave in cascade test - NSCBC boundary condition

CaseName	Link	Info	Time
001-naca65-NSCBC-backward-sineWave-Ux1Uy1	sinWaveCascade	xxx ｜ 40cores, 0.0192 s， 153s

Gallery

• 2D room NSCBC vs walls