Post on 18-Aug-2020
© Zeus Numerix Pvt. Ltd.
Presentation of Results for DPW4
4th AIAA CFD Drag Prediction Workshop 20th – 21st June 2009, San Antonio, TX, USA
Basant Kumar Gupta bkgupta@zeusnumerix.com
Venkatesh G. venkatesh@zeusnumerix.com
Presenta(onofResultsforAIAADPW‐42
Contents
Background GridGenera(onDetails Simula(onSetup
Descrip(onofResults FutureWork
Presenta(onofResultsforAIAADPW‐43
Background
ZeusNumerixwasincorporatedinAugust2004,India
DevelopsproprietaryCFDsimula(onpackagescoveringmeshgenera(on,flowsolver,visualiza(onandparalleliza(onmodules
GridZ–StructuredMul(‐blockMeshGenerator
FlowZ–CompressibleNSsolver;Pressurecorrec(onbasedsolverforIncompressibleflow
ViewZ–Scien(ficVisualizer AllmodulesconnectedthroughCGNSFile.Compa(blewithotherthird
partypackagesthroughthisfileformat
Wedeliversolu(onsandcustomizedapplica(onspecificdesignsoTwares(CFD,FEA)toourclients
Presenta(onofResultsforAIAADPW‐44
Mesh Generation
MeshisgeneratedonBodyWingTail(iH=0)configura(on
Block‐structuredmeshgeneratedusingGridZ.
Ini(almeshtookapproximately10days
Ogridgeneratedaroundthebody,wingandtail,whichismuchmoreefficientthanC‐Htopology
Requirementofhighlyclusterednearwallcellsnearwing&tail(pposedmeshqualityissues
3levelsofgridweregeneratedusingsameblocktopology
Numberofblocksineachare326
Presenta(onofResultsforAIAADPW‐45
Mesh Generation
The distribution of blocks on the surface and the volume mesh on symmetry plane
Presenta(onofResultsforAIAADPW‐46
Mesh Generation
Mesh VolumeCells SurfaceMesh
Fuselage Wing Tail
Coarse 4,369,091 28,849 18,941 8,338
Medium 15,365,720 80,672 63,800 32,120
Fine 42,520,772 183,302 136,798 67,640
Near Wall Cell Distance Distribution
Wing
Tail
Upper Lower Upper Lower
Presenta(onofResultsforAIAADPW‐47
Computational Grids, y+
Wing
Tail
Upper Lower
Upper Lower
Mesh satisfies wall clustering for low Re turbulence model
Presenta(onofResultsforAIAADPW‐48
Method
FlowZ–DevelopedatZeusNumerix&IITBombay
Finitevolumeformula(on
Mul(‐blockwith1‐1mapping
HLLCscheme
SpalartAllmarasturbulencemodel,fullN‐S
Explicit(memarching
Meshsequencingforaccelera(on
RunsonparallelmachinesthroughMPI
Presenta(onofResultsforAIAADPW‐49
Computational Platform
ParallelProcessingDoneonCDAC’sgg‐blr(GridCompu(ngResourceatBangalore)(hhp://www.cdac.in)
Opera(ngsystem:RedhatEnterpriseVersion
3.16GHzXeonprocessor
NASACRMmediumgridrunon96processors(12nodes)
ConvergencereachedaTer100,000explicititera(ons
Roughly128hoursofwallclock(meneeded
Wouldhavebeenfasterifmeshsequencingwasu(lized
Presenta(onofResultsforAIAADPW‐410
Grid Convergence
4.4M15.4M
0.015
0.020
0.025
0.030
0.035
0.040
0.045
0.0E+00 1.0E‐05 2.0E‐05 3.0E‐05 4.0E‐05
Cd
Cd‐Pr
Cd‐Sf
N‐2/3
Cd
PS: Simulations on fine mesh is in progress
NASA CRM, CL = 0.5, Re = 5 Million, iH = 0o
Difficult to judge quality of results in absence of any reference
Coarse Medium
AoA 3.1o 3.0o
Cl 0.498 0.496
Cd 0.0415 0.0406
Cm ‐2.376 ‐2.386
Presenta(onofResultsforAIAADPW‐411
Surface Streamline
BLBUB
FSBUB
WLBUB
FSEYEB, BLEYEB, WLEYEB
FSEYEW, BLEYEW, WLEYEW
Wing
Fuselage
Dividing Streamlines
Tail
Fuselage
Separation Bubble on Tail Upper Surface
Except for near fuselage region, separation absent at rest of trailing edge, both wing & tail
Presenta(onofResultsforAIAADPW‐412
Grid Density effect on Cp, Wing Sections
Cp
Cp
y = 121.46 in y = 151.07 in y = 396.77 in
y = 1145.18 in y = 978.15 in y = 581.15 in
Coarse Medium
Presenta(onofResultsforAIAADPW‐413
Grid Density effect on Cf, Wing Sections
Cf
Cf
y = 121.46 in y = 151.07 in y = 396.77 in
y = 1145.18 in y = 978.15 in y = 581.15 in
Coarse Medium
Presenta(onofResultsforAIAADPW‐414
Discussion & Future Work
CLconvergedto0.5+/‐0.005
Inabsenceonfinemeshresults,notsureifmediummeshachievesasympto(cconvergence
Keentogetareferencebasedonresultsfromotherpar(cipants
DerivingexperiencefromearlierDPW,meshquality/topologymayberequiredtolookinto
Performthefinegridcomputa(on
Computedragpolar&caseswithdeflec(ontotail
ExploreSSTturbulencemodel
ThankYou