01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | /*************************************************************************************************** THIS CODE ILLUSTRATES HOW TO CONVERT AN ANALYTICAL SOLUTION FROM POLAR COORDINATES TO CARTESIAN COORDINATES AND SUBSEQUENTLY BE USED TO INITIALIZE A FLUENT SIMULATION THIS ONLY WORKS FOR 2D SIMULATIONS. Coded by Tony Saad, © 2008 downloaded from: http://pleasemakeanote.blogspot.com/***************************************************************************************************/#include "udf.h"#define Pi 3.141592653DEFINE_INIT(Initialize_Velocity_Field, theDomain){ real xCentroid=0.0; /* abscissa of the cell centroid */ real yCentroid = 0.0; /* ordinate of the cell centroid */ real rCentroidMagnitude = 0.0; /* magnitude of the position vector */ real theta = 0.0; /* angle made by the position vector and the x axis */ real uR = 0.0; /* radial velocity (given by the analytical solution) */ real uRx =0.0; /* x projection of the radial velocity */ real uRy = 0.0; /* y projection of the radial velocity */ real uTheta = 0.0; /* tangential velocity (given by the analytical solution) */ real uThetax = 0.0; /* x projection of the tangential velocity */ real uThetay = 0.0; /* y projection of the tangential velocity */ /*declare thread variables*/ cell_t theCell; real cellCentroidCoordinates[ND_ND]; real origin[ND_ND]; Thread* theThread; /*-------------------------------------------*/ /* SET THE LOCATION OF THE ORIGIN */ origin[0] = 0.0; origin[1] = 0.0; /*-------------------------------------------*/ /* Loop over all cell threads in the domain*/ thread_loop_c(theThread,theDomain) { /* loop over all cells in the domain thread */ begin_c_loop_all (theCell,theThread) { /* get the centroid of the current cell */ C_CENTROID(cellCentroidCoordinates,theCell,theThread); /* take into account the location of the origin */ cellCentroidCoordinates[0] -= origin[0]; cellCentroidCoordinates[1] -= origin[1]; /* store the centroid location for ease of access */ xCentroid = cellCentroidCoordinates[0]; yCentroid = cellCentroidCoordinates[1]; /* compute the radius of the current cell */ rCentroidMagnitude = NV_MAG(cellCentroidCoordinates); /*-------------------------------------------*/ /* DEFINE THE RADIAL AND AXIAL VELOCITIES */ /* ENTER YOUR ANALYTICAL SOLUTION HERE */ uR = - rCentroidMagnitude; uTheta = 1/(rCentroidMagnitude + 1/rCentroidMagnitude); /*-------------------------------------------*/ /* compute the angle made by the position vector and the x-axis */ theta = atan(fabs(yCentroid/xCentroid)); if (xCentroid<=0 && yCentroid>=0) { theta = Pi - theta; } else if (xCentroid<=0 && yCentroid<=0) { theta += Pi; } else if (xCentroid>0 && yCentroid<0) { theta =2*Pi - theta; } /* compute the x and y components of the radial velocity */ uRx = uR*cos(theta); uRy = uR*sin(theta); /* compute the x and y components of the tangential velocity */ uThetax = uTheta*cos(theta + Pi/2); uThetay = uTheta*sin(theta + Pi/2); /*set the x and y velocities in fluent*/ C_U(theCell,theThread) = uRx + uThetax; C_V(theCell,theThread) = uRy + uThetay; } end_c_loop_all (theCell,theThread) }} |
