----------------- FILE NUMBER 30----------------- 1. FLOW TITLE: CASE 0112; HINZE, J. O.; SECONDARY CURRENTS IN THE TURBULENT FLOW THROUGH A STRAIGHT CONDUIT. 2. REVISION DATE: FEBRUARY 8, 1981. 3. EVALUATOR: GESSNER, F. B., UNIVERSITY OF WASHINGTON, DEPARTMENT OF MECHANICAL ENGINEERING, FU-10, SEATTLE, WASHINGTON 98195. 4. DATE AND LOCATION OF EXPERIMENT: 1971, DELFT UNIVERSITY OF TECHNOLOGY, DEPARTMENT OF MECHANICAL ENGINEERING, DELFT, THE NETHERLANDS. 5. ABSTRACT: THIS EXPERIMENT WAS CARRIED OUT WITH TURBULENT FLOW THROUGH A CONDUIT OF RECTANGULAR CROSS-SECTION WITH LARGE ASPECT RATIO. ONE OF THE WALLS WAS MADE ROUGH, EXCEPT FOR A CENTRALLY LOCATED STRIP. SECONDARY CURRENTS OCCURRED IN THE REGIONS OF TRANSITION FROM SMOOTH TO ROUGH WALL-CONDITION. THE MAIN PURPOSE OF THE INVESTIGATION WAS TO CHECK THE ADMISSIBILITY OF SIMPLIFYING ASSUMPTIONS MADE TO THE MECHANICAL-ENERGY BALANCE EQUATION. THE RESULT OF THE MEASUREMENT INDEED JUSTIFIED THE NEGLECT OF UNIMPORTANT TERMS OF THIS EQUATION, LEADING TO THE FOLLOWING RULE. WHEN IN A LOCALIZED REGION, THE PRODUCTION IS MUCH GREATER(SMALLER) THAN THE VISCOUS DISSIPATION, THERE MUST BE A SECONDARY CURRENT THAT TRANSPORTS TURBULENCE-POOR FLUID INTO THIS REGION AND TURBULENCE-RICH FLUID OUTWARDS FROM THE REGION. ALL MEASUREMENTS WERE MADE AT X/DH = 126, WHERE X IS MEASURED FROM THE DUCT ENTRANCE. THE FLOW CAN BE REGARDED AS FULLY DEVELOPED AND INDEPENDENT OF INLET FLOW CONDITIONS. THE NON-UNIFORM WALL CONDITION ALONG THE LOWER WALL (Y=0) GIVES RISE TO A FAIRLY SECONDARY FLOW WHICH IS DIRECTED AWAY FROM THE WALL NEAR THE PLANE OF SYMMETRY (Z = 0). THIS TRANSVERSE MEAN FLOW APPEARS IN THE FORM OF TWO SECONDARY FLOW CELLS IN THE CENTRAL PORTION OF THE DUCT WHICH DISTORTS LINES OF CONSTANT AXIAL MEAN-VELOCITY. AS A RESULT OF THIS DISTORTION, THE MAXIMUM VELOCITY DOES NOT OCCUR IN THE PLANE OF SYMMETRY, BUT INSTEAD AT TWO LOCATIONS. THE DATA WHICH ARE AVAILABLE FOR PURPOSES OF COMPARISON INCLUDE THE GLOBAL VARIATION OF LINES OF CONSTANT AXIAL MEAN-VELOCITY, AND MEAN FLOW AND TURBULENCE DATA ALONG THE PLANE OF SYMMETRY. THE DATA ALSO INCUDE LOCAL FRICTION VELOCITIES MEASURED WITH A PRESTON TUBE IN THE PLANE OF SYMMETRY. RESULTS WERE OBTAINED FOR DISTRIBUTION OF THE ISOVELS IN THE CROSS SECTION. THE STRONG DEVIATIONS AROUND THE PLANE OF SYMMETRY OF THE ISOVELS FROM THOSE FOR A DUCT WITH ALL WALLS SMOOTH, SUGGEST A RELATIVELY STRONG SECONDARY FLOW AWAY FROM THE BOTTOM WALL. EXPERIMENTS WITH A DIFFERENT CONFIGURATION HAVE REVEALED THAT THE SECONDARY CURRENT MAY HAVE A DIRECTION OPPOSITE TO THE ONE WHICH WOULD BE CONCLUDED FROM THE SHAPE OF THE ISOVELS. IT MAY BE NOTED THAT THE ABSOLUTE MAXIMUM VELOCITY IN THE CROSS SECTION IS NOT IN THE PLANE OF SYMMETRY, BUT IN THE PLANES Z = +/-0.066 M. ALL MEASUREMENTS REPORTED HERE PERTAIN TO THE PLANE OF SYMMETRY Z = 0. 6. REFERENCES: 1. HINZE, J. O., EXPERIMENTAL INVESTIGATIONS ON SECONDARY CURRENTS IN THE TURBULENT FLOW THROUGH A STRAIGHT CONDUIT, APPLIED SCIENTIFIC RESEARCH, VOL. 28, 1973,PP.453-465. 2. HINZE, J. O., EXPERIMENTAL INVESTIGATIONS ON SECONDARY CURRENTS IN THE TURBULENT FLOW THROUGH A STRAIGHT CONDUIT, REPORT WTHD 27, LABORATORY FOR AERO-AND HYDRODYNAMICS, DELFT UNIVERSITY OF TECHNOLOGY, AUGUST, 1971. (ALSO AVAILABLE AS NBS NO. N73-14279). 3. GESSNER, F. B., FINAL REPORT: CORNER FLOW DATA EVALUATION, DEPARTMENT OF MECHNICAL ENGINEERING, UNIVERSITY OF WASHINGTON, 1980. 7. INSTRUMENTATION: DISTRIBUTIONS OF MEAN AXIAL VELOCITIES (ISOVELS) WERE MEASURED WITH A TOTAL HEAD-TUBE OF 0.002 M EXTERNAL DIAMETER. A PRESTON TUBE (EXTERNAL DIAMETER 0.001 M, DIAMETER RATIO 0.6) WAS USED FOR MEASURING THE WALL SHEAR-STRESS. ALL TURBULENCE VELOCITY MEASUREMENTS WERE MADE WITH HOT-WIRE ANEMOMETERS (PLATINUM-COATED TUNGSTEN WIRE OF 5 MICRON DIAMETER, 0.001 M LENGTH) OPERATING IN THE CONSTANT-TEMPERATURE MODE. 8. EXPERIMENTAL PARAMETERS: THE TEST SETUP CONSISTED ESSENTIALLY OF A BLOWER AND A LONG HORIZONTAL STRAIGHT DUCT OF UNIFORM RECTANGULAR CROSS SECTION OF 0.45*0.09 M**2, WITH THE LONG SIDES IN THE HORIZONTAL PLANE. AT THE BLOWER SIDE, I.E. AT THE ENTRANCE SECTION OF THE DUCT A GAUZE SCREEN AND A LENGTH OF HONEYCOMB REDUCED POSSIBLE LARGE IRREGULARITIES IN THE AIR FLOW CAUSED BY THE BLOWER. SPECIAL PROVISIONS WERE MADE FOR PREVENTING TRANSFER OF VIBRATIONS FROM THE BLOWER TO THE DUCT. THE DUCT HAD A LENGTH OF 19 M, SO THAT WITH A HYDRAULIC DIAMETER OF 0.15 M, FULLY DEVELOPED TURBULENT FLOW WAS OBTAINED AT THE END SECTION OF THE DUCT THE MEASUREMENTS WERE MADE IN A CROSS-SECTION. THE MAXIMUM VELOCITY 15 M/SEC., CORRESPONDING WITH REYNOLDS NUMBER ROUGHLY EQUAL TO 1.5*10**6. THREE OF THE SIDE WALLS WERE SMOOTH, WHEREAS THE BOTTOM WALL WAS MADE ROUGH ARTIFICIALLY, EXCEPT FOR THE CENTRAL PART OF 0.1 M WHICH REMAINED SMOOTH. FOR THE ROUGH PARTS PLASTIC GRAINS WERE GLUED TO THE WALL. THE AVERAGE ROUGHNESS HEIGHT SO OBTAINED WAS 0.004 M. DUCT DIMENSIONS: A = 0.092 M HEIGHT OF THE DUCT. B = 0.225 M (WIDTH OF THE DUCT)/2. C = 0.050 M (WIDTH OF SMOOTH BOTTOM WALL)/2. L = 19.00 M TOTAL LENGTH OF THE DUCT. AR = 5.00 ASPECT RATIO OF THE DUCT. DH = 0.150 M HYDRAULIC DIAMETER OF THE DUCT. OPERATING CONDITIONS: UMAX0 = 14.40 M/SEC. (MAXIMUM VELOCITY IN PLANE OF SYMMETRY). UMAX = 15.00 M/SEC. (MAXIMUM VELOCITY IN DUCT CROSS-SECTION). REMAX = UMAX*DH/NU = 1.5*10**5 NOTE: U/UMAX = 1.00 AT Y/A = 0.568 AND Z/A = 0.707 9. MEASURED AND INFERRED VARIABLES: X DIRECTION OF THE MAIN FLOW, (M). Y DIRECTION PERPENDICULAR TO THE BOTTOM WALL, POSITIVE UPWARD, (M). Y1 DIRECTION PERPENDICULAR TO THE UPPER WALL, POSITIVE DOWNWARD, (M). Z TRANSVERSE DIRECTION, (M). NU KINEMATIC VISCOSITY. U,V,W MEAN-VELOCITY COMPONENT IN X, Y, Z DIRECTION, (M/SEC.). USTAR FRICTION VELOCITY ON THE BOTTOM WALL, (M/SEC.). U1STAR FRICTION VELOCITY ON THE UPPER WALL, (M/SEC.). U2,V2,W2 REYNOLDS NORMAL STRESS COMPONENTS REFERRED TO X,Y,Z COORDINATE SYSTEM, (M**2/SEC.**2). U*V,U*W,V*W REYNOLDS SHEAR STRESS COMPONENTS REFERRED TO X,Y,Z COORDINATE SYSTEM, (M**2/SEC.**2). Y/A NONDIMENSIONAL DISTANCE. Z/A NONDIMENSIONAL DISTANCE. U/UMAX NONDIMENSIONAL VELOCITY. U/USTAR NONDIMENSIONAL VELOCITY. U/U1STAR NONDIMENSIONAL VELOCITY. U/UMAX0 NONDIMENSIONAL VELOCITY. EPSILON VISCOUS DISSIPATION RATE OF TURBULENT MOTION, (M**2)/(SEC.**3). 10. MEASUREMENT UNCERTAINTY: NONE SPECIFIED. 11. TAPE ORGANIZATION: THE TAPE IS A 2400 FOOT, 9 TRACK, ODD PARITY, PHASE ENCODED, UNLABELLED TAPE WRITTEN AT A DENSITY OF 1600 BITS PER INCH ACCORDING TO EBCDIC CODE. THE RECORD FORMAT IS FIXED AND BLOCKED; RECORD LENGTH = 80 BYTES; BLOCKSIZE = 8000 BYTES NORMALIZED DATA ARE CREATED FROM MEASURED DATA AS FOLLOWS: XNORM = (X - XMIN)/(XMAX - XMIN) NORMALIZED VALUES ARE INTEGERIZED BY MULTIPLYING BY 10000 AND ROUNDING UP OR DOWN TO THE NEAREST INTEGER. IXNORM = XNORM * 10000. THUS EACH NORMALIZED DATUM IS WRITTEN ONTO TAPE AS AN INTEGER VALUE BETWEEN 0 AND 10000. ALL NULL DATA ARE WRITTEN AS 20000 THE EQUATION DESCRIBING THE RELATION BETWEEN ACTUAL DATA AND THE NORMALIZED DATA ON TAPE IS X = XMIN + (((XMAX - XMIN) * IXNORM)/10000.) WHERE X, XMAX AND XMIN ARE REAL AND IXNORM IS INTEGER. FILE# NREC CONTAINS FORMAT COMMENTS 1 - TEXT FILE - CONTAINS ITEMS 1 TO 11 OF THIS WRITE-UP 2 36 Y/A,Z/A,Y/A,Z/A, 6E13.6/ RECORDS 1&2 - MAXIMUM Y/A,Z/A,Y/A,Z/A, 6E13.6 VALUES Y/A,Z/A,Y/A,Z/A FOR U/UMAX = 0.60, 0.70, 0.80, 0.90, 0.95 RESPECTIVELY. Y/A,Z/A,Y/A,Z/A, 6E13.6/ RECORDS 3&4 - MINIMUM Y/A,Z/A,Y/A,Z/A, 6E13.6 VALUES Y/A,Z/A,Y/A,Z/A FOR U/UMAX = 0.60, 0.70, 0.80, 0.90, 0.95 RESPECTIVELY. Y/A,Z/A,Y/A,Z/A, 12I6 RECORDS 5 - 36 Y/A,Z/A,Y/A,Z/A, NORMALIZED VALUES Y/A,Z/A,Y/A,Z/A FOR U/UMAX = 0.60, 0.70, 0.80, 0.90, 0.95 RESPECTIVELY. 3 20 Y*USTAR/NU,U/USTAR, 4E13.6 RECORD 1 - MAXIMUM Y1*U1STAR/NU,U/U1STAR VALUES Y*USTAR/NU,U/USTAR, 4E13.6 RECORD 2 - MINIMUM Y1*U1STAR/NU,U/U1STAR VALUES Y*USTAR/NU,U/USTAR, 4I6 RECORDS 3 - 20 Y1*U1STAR/NU,U/U1STAR NORMALIZED VALUES 4 38 Y,U/UMAX0,V, 4E13.6/ RECORDS 1&2 - MAXIMUM SQRT(U2)/UMAX0, 4E13.6 VALUES SQRT(V2)/UMAX0, SQRT(W2)/UMAX0, - U*V,EPSILON Y,U/UMAX0,V, 4E13.6/ RECORDS 3&4 - MINIMUM SQRT(U2)/UMAX0, 4E13.6 VALUES SQRT(V2)/UMAX0, SQRT(W2)/UMAX0, - U*V,EPSILON Y,U/UMAX0,V, 8I6 RECORDS 5 - 38 SQRT(U2)/UMAX0, NORMALIZED VALUES SQRT(V2)/UMAX0, SQRT(W2)/UMAX0, - U*V,EPSILON A SAMPLE PROGRAM FOR READING FILE 3 AND PRINTING, IS SHOWN BELOW. THE JCL SHOWN IS FOR THE STANFORD CIT FACILITY. CHECK WITH YOUR OWN COMPUTER INSTALLATION FOR THE EXACT JCL NEEDED. //TAPE JOB BZC$NJ /*SETUP TAPE=1,INPUT=(LIBRARY NUMBER ASSIGNED TO TAPE) // EXEC FORTCG //FORT.SYSIN DD * C TO READ FILE 3 OFF TAPE C PRINT MAXIMAS AND MINIMAS OF ALL THE VARIABLES C PRINT NORMALIZED INTEGERIZED VALUES OF ALL THE VARIABLES. INTEGER UBAR(20),U(20),U1BAR(20),U1(20) READ (23,30) UBARMX,UMX,U1BAMX,U1MX READ (23,30) UBARMN,UMN,U1BAMN,UIMN DO 10 I = 1, 18 10 READ (23,40) UBAR(I),U(I),U1BAR(I),U1 WRITE (6,50) UBARMX,UMX,U1BAMX,U1MX WRITE (6,50) UBARMN,UMN,U1BAMN,U1MN DO 20 I = 1, 18 20 WRITE (6,60) UBAR(I),U(I),U1BAR(I),U1(I) 30 FORMAT(4E13.6) 40 FORMAT(4I6) 50 FORMAT(1X,4E13.6) 60 FORMAT(1X,4I6) STOP END //GO.FT23F001 DD UNIT=T1600,VOL=SER=(TAPE LIBRARY NUMBER), // DISP=(OLD,KEEP),DCB=(RECFM=FB,LRECL=80,BLKSIZE=8000,DEN=3), // LABEL=(3,NL) // -------------- END OF FILE NUMBER 30------------- ----------------- FILE NUMBER 31----------------- 0.200000E 00 0.238000E 01 0.974000E 00 0.233800E 01 0.958000E 00 0.223500E 01 0.931000E 00 0.209100E 01 0.890000E 00 0.183700E 01 0.823000E 00 0.132800E 01 0.106000E 00 0.146700E 01 0.510000E-01 0.000000E 00 0.113000E 00 0.000000E 00 0.175000E 00 0.000000E 00 0.240000E 00 0.000000E 00 0.328000E 00 0.000000E 00 0 0 433 0 1704 0 2843 0 5061 0 8161 0 1276 2683 227 521 1171 545 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