Twenty-Third Symposium on Naval Hydrodynamics (2001) / Chapter Skim
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An Unstructured Multielement Solution Algorithm for Complex Geometry Hydrodynamic Simulations
An Unstructured Multielement Solution Algorithm for Complex Geometry Hydrodynamic Simulations
Pages 897-909
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From page 897... ...
The present parallel mstructured viscous -I w solver is based on c coarseg cmed domain decomposition for concurrent solution withm subdomcins cssig cd to multiple processors All tetmhedLcl Ed multielement mshuctured meshes in this work are generated with m cdvarming normal methodology for he bo mdary layer elements, md m AFLR cdvarmmg f ontflocal rffom ction methodology for he isohopic elements es given in [20] This procedure allows for the generation of high quality mshuctmed g ids suitable for simulation of high R y olds m mbff viscous flows All geometry preparation md surface g id generation is performed using SohdLhl sh [21]
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From page 898... ...
(6) where /mmd /q iimZ 6he molec br imd eddy vi iosities, re pecti dy NUMERICAL APPROACE he bli seliZ Z flow sol x is ii node-centered, flmite vol me, implicit sch me ii pplied to gff xti I mstZ itured g idswi6hnonsimpliciilelements heflowvariiiblesti e stored s t the Z tices imd ~ fli cc mteg s Is iire evaluated on 6he mediim dual surro mdingeiich of 6hese Z ti yr he nono xlirpping control vol mes fommed by the mediim dum completely co x 6he domli in, imd form s mesh thtit is dual to 6he elementtil g id h n, ii o' Z-to-oZ Z mlippmg exists betweff` the edges of the origi'~I g id imd the faes of 6he conhol vol mes he sol Ztion ii Igorithm consists of 6he foil wmg bti sic steps: reconsh ition of 6he sol rtion tti tes ii t the control vol me fli ies, evaluation of the flux integ ii Is for eiich conhol d me, imd the e d rtion of 6he sol rtion (2)
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From page 899... ...
63 \ ,, q 1-6, <~{ :-t, of 1-6, q - - - (11) where 41'' = q" ~—q" A flkst order acurti te in time Enler implicit scheme is given by the choices 9~ = i, 63 = 0 Correspondmgly, s second order time acurti te Enler implicit scheme is given by 6 ~ = i, t93 = 1/2 Si ce 6 ~ = ~ for both time discretizations used in 6his work, Equation I I cim be fm6her simplifled: ~—930f (q )
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From page 900... ...
> f(U) Boundary Conditions Viscous conditions s e e forced by modffymg 6he Imeii sy tem such 6~t no ch mge is ii 11ow d m the velocity, imd the pressure is dkiven acordmg to 6he imbti ltim m the contmnity equation in the bo mdii y control vol me [12]
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From page 901... ...
I ;~ [E ~ I it ~ ~ t~a Matrix-Vector Multiply Update i\Q bu`~ iFb~1 Figure 1: Iteration hierarchy used for the parallel unstructured solution algorithm for the mean How, and the convective terms are computed via pure unwinding. Appropriate consideration is given to maintain positive operators in the formation of the Jacobian matrix for the implicit solution of the transport equation(s)
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From page 902... ...
Further, the body itself loosely resembles a submarine hull, which has obvious relevance for a solution algorithm with a hydrodynamic focus. Experimental data is available from Meter t351 for 3D boundary layers developing on the prolate spheroid; this data is in the form of surface pressure distributions for steady Hows at angle Figure 3: Pressure distribution on body surface and at C/L = 0.83 of attack and for unsteady pitch/plunge/turn body motions.
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From page 903... ...
°oo°~ x/L=.83 'a ~ _ : 30 60 90 1 20 1 50 1 80 circumferential angle :~ x/L=.77 °° too GDo:D I x/L=.9O 4=~=/ ) 3 30 60 90 1 20 1 50 1 80 circumferential angle Figure 5: Unstructured algorithm compared to experimental data; stations C/L = 0.69, 0.77, 0.83, 0.90 Figure 6: Surface grid for the fishing vessel case; experimental data is presented for r/R = 0.69 NOAA FRY-40 Hull The objective of the NOAA FRY-40 Howfield study is to examine the fluid behavior in the vicinity of the propeller appendage.
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From page 904... ...
The axial force, normal force, and pitching moment are computed and compared to the corresponding experimental data in Figures 11 4: -0.25 -0.50 o J ~0 I r/R = 0.690 '= = ~ I: 90 1 80 circumferential angle (degrees) —Vx, computed —Vr, computed —Vt, computed 0 Vx, experimental Vr, experimental Vt, experimental 270 360 Figure 8: Velocity profiles for the fishing vessel case at r/R = 0.69; q—w turbulence model Figure 9: Volume grid in the vicinity of the stern appendages for the SUBOFF model
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From page 905... ...
7he q—m tmbulence model is utili:D:d in bodh cases As shown in Figme 14, eg eement betweff~ experiment md computation is excellent on the eft part of fhe hull (where meesurements ReRb dab ~S~b~; Onnsm~e ~: Vt Figme 12: Nommel force coefificient for fhe SUBOFF model elDeRi dab 1 | Vs omem ~ode ~ r ~t t :-*
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From page 906... ...
The primary purpose of the nonappended 5415 hull simulation is to examine nominal wake How patterns. The fully appended hull with propulsors is intended to highlight the capability of the overall solution methodology to model extremely complex geometries coupled with complex unsteady Howfields.
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From page 907... ...
Implicit upwind solution algorithms for three-dimensional unstructured meshes. AIAA Journal, 31~5)
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From page 908... ...
Roger Briley Parcllel solution of viscous incompressible fl w on multiblock structured g ids using MPI Ponollel Computohonol Fhid Dyn mics: Impl m mt tions ond Rffult UsingPanollel Comput rS, pages 601 608, 1995 [20] DavidL Marc m mdJ AdamGci6her Mixedelement type mshuctmed g id ge ffction for viscous fl w cpplications A AA Popen 99 3252, 1999 14th A AA CFD Co ference, June 1999, No folk, VA [21]
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From page 909... ...
Robert F Roddy investigation of the stability md control charateristics of several co flgmations of the DARPA SUBOFF model from ccptive model experiments Techmiccl R port DTRC/SHD-1298 08, David Tcylor R search C nter, Bethesda, Marykmd 20084-5000, September 1990 ~, f T
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