TALK=T;RUN( 1, 1) ** LOAD(x106) from the x Input Library TEXT(RNG KE-2D FLOW IN TURNAROUND DUCT :T106 TITLE DISPLAY This case concerns plane, two-dimensional, incompressible flow through a 180 degree turnaround duct, as studied experimentally by Monson & Seegmiller (1988). The duct has a width W=0.0381m and an aspect ratio of 10. The inlet and outlet planes are located 3.5W upstream and downsteam of the bend, respectively. The inner radius of the bend is 0.01905m, which corresponds to a curvature ratio of 0.5. The Reynolds number based on duct width is 1.E5, and the Dean number is 7.071E4. The flow exhibits large streamline curvature with flow relaminarisation along the inner convex wall together with the fromation of a separation zone near the bend exit on the inner (convex) surface of the duct. The turnaround duct is representative of many flows of engineering interest, such as flow in the turnaround duct of the Space-Shuttle-Main-Engine powerhead. Calculations are made with several high-Re forms k-e and k-w model, and the calculation employs a relatively coarse non-uniform mesh of NY=25 and NZ=80. The standard k-e and k-w models do not predict the occurence of separation along the inner wall at the exit of the U-bend. The other variants of these models do predict this feature, but with varying size of the separation bubble. The current solutions remain sensitive to mesh numbers. Typically, depending on the turbulence model used, 450 to 900 sweeps are required for complete convergence. Low-Reynolds-number modelling, as exemplified by Library Case T214, is recommended to predict the important features of this flow. ENDDIS D.Monson, D. & Seegmiller, H. L., "Comparison of LDV measurements and Navier-Stokes solutions in a two-dimensional 180 degree turn-around duct." AIAA Paper AIAA 89-0275. (1988). D.J.Monson, H.L.Seegmiller, P.K.McConnaughey and Y.S.Chen, 'Comparison of experiment with calculations using curvature-corrected zero and two-equation turbulence models for a two-dimensional U-duct', AIAA 90-1484, (1990). J.L Yin, D.Z Wang, H Cheng & W.G.Gu,"Assessment of RANS to predict flows with large streamline curvature", IOP Conference Series: Materials Science and Engineering, Volume 52, Topic 2, (1990). V.A. Sandborn & J.C.Shin, "Water Flow Measurements in a 180 Degree Turnaround Rectangular Duct", NASA Contractor Report No: 36354, June (1989). PHOTON USE p view x gr ou x 1 msg velocity vectors vec x 1 sh msg pressto continue pause vec off; redr msg contours of normalised w velocity resolutes con w1nr x 1 fi;0.1 msg press to continue pause con del; redr msg contours of turbulence intensities con tint x 1 fi;0.1 msg Press and then to END pause con del; redr msg contours of pressure coefficients con cp x 1 fi;0.1 msg press to continue pause ENDUSE GROUP 1. Run title BOOLEAN(KWMOD);KWMOD=F CHAR(CTURB,TLSC) REAL(REYNO,WIN,TKEIN,EPSIN,WIDTH,LENGTH,YAXIS,MASIN,DTF,DEAN) REAL(RADBI,RADBO,RADC,CURVRT) ** Reynolds number REYNO=1.E5 ** Duct width & other dimensions WIDTH=.0381;YAXIS=1.5*WIDTH;LENGTH=3.5*WIDTH ** Inlet values WIN=26.25;TKEIN=(0.05*WIN)**2;EPSIN=TKEIN**1.5*0.1643/(0.09*WIDTH) ** Dean Number RADBO=YAXIS;RADBI=YAXIS-WIDTH;RADC=YAXIS-0.5*WIDTH CURVRT=0.5*WIDTH/RADC ! Curvature ratio DEAN =REYNO*(CURVRT)**0.5 ! Dean number DEAN;CURVRT GROUP 6. Body-fitted coordinates or grid distortion BFC=T;NONORT=T;NX=1 NY=25;NZ=80 GSET(D,NX,NY,NZ,1.0,WIDTH,LENGTH) GSET(P,A,0.0,0.0,LENGTH);GSET(P,B,0.0,WIDTH,LENGTH) GSET(P,C,1.0,0.0,LENGTH);GSET(P,D,1.0,WIDTH,LENGTH) GSET(L,LAB,A,B,NY,S1.7);GSET(L,LBD,B,D,NX,1.0) GSET(L,LCD,C,D,NY,S1.7);GSET(L,LCA,C,A,NX,1.0) GSET(F,FABCD,A,-,B,-,D,-,C,-) GSET(M,FABCD,+J+I,1,1,1,TRANS) GSET(C,K81,F,K1,+,0.0,0.0,0.0) GSET(C,K81,F,K81,+,0.0,(YAXIS+0.5*WIDTH),0.0) ** k71-k51 cells in the outlet length GSET(C,K51,F,K81,+,0.0,0.0,-LENGTH,INC,0.8) ** k51-k21 cells in the bend GSET(C,K21,F,K51,RX,-3.14159,YAXIS,0.0,INC,1.0) ** k21-k1 cells in the inlet length GSET(C,K1,F,K21,+,0.0,0.0,LENGTH,INC,1.2) ** Set wup=t to account better for the high curvature of the w resolute... WUP=T GROUP 7. Variables stored, solved & named SOLVE(P1,V1,W1);SOLUTN(P1,Y,Y,Y,N,N,N);STORE(ENUT,LEN1,YPLS,STRS) SOLUTN(V1,P,P,P,P,P,N);SOLUTN(W1,P,P,P,P,P,N) MESG( Enter the required turbulence model: MESG( CK - Chen-Kim k-e model MESG( KE - Standard k-e model MESG( RNG - RNG k-e model (default) MESG( KW - Wilcox k-w model MESG( RKE - Realisable k-e model MESG( KWR - Wilcox 2008 k-w model MESG( KWS - k-w SST model MESG( MESG( READVDU(CTURB,CHAR,RNG) CASE :CTURB: OF WHEN CK,2 + TEXT(CK KE-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Chen-Kim k-e model + TURMOD(KECHEN);TLSC=EP WHEN KE,2 + TEXT(KE-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Standard k-e model + TURMOD(KEMODL);TLSC=EP WHEN KW,2 + TEXT(KW-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Wilcox 1988 k-w model + TURMOD(KWMODL);TLSC=OMEG + STORE(EP);EPSIN=EPSIN/(0.09*TKEIN) WHEN RNG,3 + MESG(RNG k-e model (default) + TURMOD(KERNG);TLSC=EP + STORE(ETA,ALF,GEN1);KELIN=1 + OUTPUT(ALF,Y,N,P,Y,Y,Y);OUTPUT(ETA,Y,N,P,Y,Y,Y) WHEN RKE,3 + TEXT(RKE-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Realisable k-e model + TURMOD(KEREAL);STORE(C1E);TLSC=EP + OUTPUT(CMU,P,P,P,P,Y,Y);OUTPUT(C1E,P,P,P,P,Y,Y) + STORE(DUDY,DUDZ) ! for 2D BFC cases UCRT is stored WHEN KWR,3 + TEXT(KWR-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Wilcox 2008 k-w model + TURMOD(KWMODLR);STORE(FBP);FIINIT(FBP)=1.0 + KWMOD=T;TLSC=OMEG;EPSIN=EPSIN/(0.09*TKEIN) + STORE(DUDY,DUDZ) ! for 2D BFC cases UCRT is stored WHEN KWS,3 + TEXT(SST-2D FLOW IN TURNAROUND DUCT :T106 + MESG(Menter k-w SST model + TURMOD(KWSST) + KWMOD=T;EPSIN=EPSIN/(0.09*TKEIN);TLSC=OMEG + STORE(BF1,BF2,GEN1,SIGK,SIGW,CDWS) + STORE(CWAL,CWBE) + FIINIT(BF1)=1.0;FIINIT(BF2)=1.0 ENDCASE STORE(CP) ! pressure coefficient (stored of CP is 2.*P1/(RHO1*WIN*WIN)) STORE(TINT) ! turbulent intensity (stored of TINT is KE^0.5/WIN) STORE(W1NR) ! normalised streamwise velocity (stored of W1NR is W1/WIN) GROUP 8. Terms (in differential equations) & devices GROUP 9. Properties of the medium (or media) ENUL=WIN*WIDTH/REYNO GROUP 11. Initialization of variable or porosity fields FIINIT(P1)=1.E-10;FIINIT(W1)=WIN FIINIT(KE)=TKEIN;FIINIT(:TLSC:)=EPSIN GROUP 13. Boundary conditions and special sources INLET(BFCIN,LOW,#1,#1,#1,#NREGY,#1,#1,1,1) VALUE(BFCIN,P1,GRND1);VALUE(BFCIN,W1,GRND1) VALUE(BFCIN,WCRT,-WIN);VALUE(BFCIN,KE,TKEIN) VALUE(BFCIN,:TLSC:,EPSIN) * Transfer density for GXBFC subroutine BFCA=RHO1 PATCH(OUTLET,HIGH,#1,#1,#1,#NREGY,#NREGZ,#NREGZ,1,1) COVAL(OUTLET,P1,1.E4,0.0) COVAL(OUTLET,V1,ONLYMS,0.0);COVAL(OUTLET,W1,ONLYMS,0.0) ** N-wall WALL (WFNN,NORTH,1,NX,NY,NY,1,NZ,1,1) ** S2-wall WALL (WFNS,SOUTH,1,NX,1,1,1,NZ,1,1) GROUP 15. Termination of sweeps LSWEEP=1000 MASIN=WIDTH*WIN*RHO1 RESREF(P1)=1.E-12*MASIN RESREF(W1)=RESREF(P1)*WIN; RESREF(V1)=RESREF(W1) RESREF(KE)=RESREF(P1)*TKEIN; RESREF(:TLSC:)=RESREF(P1)*EPSIN GROUP 16. Termination of iterations LITER(P1)=20 GROUP 17. Under-relaxation devices RELAX(P1,LINRLX,1.0);DTF=ZWLAST/WIN/NZ RELAX(W1,FALSDT,DTF); RELAX(V1,FALSDT,DTF) RELAX(KE,FALSDT,DTF); RELAX(:TLSC:,FALSDT,DTF) GROUP 22. Spot-value print-out IYMON=2;IZMON=56;NPRMON=LSWEEP GROUP 23. Field print-out and plot control NPRINT=LSWEEP;ITABL=3;NPLT=2 NYPRIN=1;NZPRIN=1;IZPRF=18;IZPRL=24;TSTSWP=-1 SPEDAT(SET,GXMONI,PLOTALL,L,T) SPEDAT(SET,OUTPUT,NOFIELD,L,T) OUTPUT(ENUT,Y,N,Y,N,Y,Y) DISTIL=T CASE :CTURB: OF WHEN KE,2 +EX(P1 )=1.232E+02;EX(V1 )=5.955E-01 +EX(W1 )=2.546E+01;EX(KE )=1.631E+01 +EX(EP )=1.237E+04;EX(STRS)=1.987E-01 +EX(YPLS)=1.564E+00;EX(LEN1)=2.564E-03 +EX(ENUT)=5.700E-03;EX(WCRT)=2.184E+01 +EX(VCRT)=6.728E+00;EX(W1NR)=9.579E-01 +EX(TINT)=1.359E-01;EX(CP )=3.575E-01 WHEN CK,2 +EX(P1 )=1.221E+02;EX(V1 )=6.210E-01 +EX(W1 )=2.506E+01;EX(KE )=4.211E+00 +EX(EP )=7.886E+03;EX(STRS)=1.590E-01 +EX(YPLS)=1.355E+00;EX(LEN1)=1.284E-03 +EX(ENUT)=1.199E-03;EX(WCRT)=2.143E+01 +EX(VCRT)=6.773E+00;EX(W1NR)=9.427E-01 +EX(TINT)=7.461E-02;EX(CP )=3.543E-01 WHEN RNG,3 +EX(P1 )=1.218E+02;EX(V1 )=6.161E-01 +EX(W1 )=2.505E+01;EX(KE )=4.140E+00 +EX(EP )=7.562E+03;EX(GEN1)=1.497E+08 +EX(ALF )=6.735E-01;EX(ETA )=3.073E+00 +EX(STRS)=1.539E-01;EX(YPLS)=1.338E+00 +EX(LEN1)=1.178E-03;EX(ENUT)=1.076E-03 +EX(WCRT)=2.142E+01;EX(VCRT)=6.760E+00 +EX(W1NR)=9.425E-01;EX(TINT)=7.357E-02 +EX(CP )=3.536E-01 WHEN RKE,3 +EX(P1 )=1.258E+02;EX(V1 )=6.976E-01 +EX(W1 )=2.512E+01;EX(KE )=8.434E+00 +EX(EP )=8.396E+03;EX(C1E )=5.088E-01 +EX(DWDZ)=5.544E+02;EX(DWDY)=1.911E+03 +EX(DVDZ)=7.194E+02;EX(DVDY)=5.628E+02 +EX(EPKE)=1.066E+03;EX(CMU )=1.149E-01 +EX(STRS)=1.593E-01;EX(YPLS)=1.371E+00 +EX(LEN1)=2.447E-03;EX(ENUT)=5.227E-03 +EX(WCRT)=2.148E+01;EX(VCRT)=6.811E+00 +EX(W1NR)=9.449E-01;EX(TINT)=1.005E-01 +EX(CP )=3.653E-01 WHEN KW,2 +EX(P1 )=1.231E+02;EX(V1 )=6.186E-01 +EX(W1 )=2.525E+01;EX(KE )=1.387E+01 +EX(EP )=1.131E+04;EX(OMEG)=1.157E+04 +EX(STRS)=1.799E-01;EX(YPLS)=1.462E+00 +EX(LEN1)=2.294E-03;EX(ENUT)=4.601E-03 +EX(WCRT)=2.163E+01;EX(VCRT)=6.742E+00 +EX(W1NR)=9.499E-01;EX(TINT)=1.253E-01 +EX(CP )=3.574E-01 WHEN KWR,3 +EX(P1 )=1.210E+02;EX(V1 )=6.148E-01 +EX(W1 )=2.507E+01;EX(KE )=4.765E+00 +EX(EP )=7.886E+03;EX(DWDZ)=4.612E+02 +EX(DWDY)=1.869E+03;EX(DVDZ)=6.264E+02 +EX(DVDY)=4.655E+02;EX(GEN1)=2.990E+08 +EX(FBP )=9.391E-01;EX(XWP )=1.359E-01 +EX(OMEG)=1.108E+04;EX(STRS)=1.586E-01 +EX(YPLS)=1.341E+00;EX(LEN1)=2.003E-03 +EX(ENUT)=1.625E-03;EX(WCRT)=2.144E+01 +EX(VCRT)=6.762E+00;EX(W1NR)=9.430E-01 +EX(TINT)=7.902E-02;EX(CP )=3.513E-01 WHEN KWS,3 +EX(P1 )=1.324E+02;EX(V1 )=7.261E-01 +EX(W1 )=2.484E+01;EX(KE )=3.674E+00 +EX(EP )=7.458E+03;EX(CWBE)=7.745E-02 +EX(CWAL)=5.177E-01;EX(CDWS)=5.039E+06 +EX(SIGW)=1.738E+00;EX(SIGK)=1.686E+00 +EX(LTLS)=9.508E-05;EX(WDIS)=7.157E-03 +EX(GEN1)=3.512E+08;EX(BF2 )=9.517E-01 +EX(BF1 )=6.855E-01;EX(OMEG)=1.154E+04 +EX(STRS)=1.445E-01;EX(YPLS)=1.281E+00 +EX(LEN1)=1.319E-03;EX(ENUT)=9.093E-04 +EX(WCRT)=2.121E+01;EX(VCRT)=6.814E+00 +EX(W1NR)=9.346E-01;EX(TINT)=6.809E-02 +EX(CP )=3.842E-01 ENDCASE LIBREF = 106 STOP