adding molecular dynamics sources/app/utility

applications/utilities/preProcessing/molConfig/velocityDistributions/uniform.H

@@ -0,0 +1,27 @@
+scalar initVelMag =
+    sqrt
+    (
+        3.0*(1.0 - 1.0 / totalZoneMols)
+       *moleculeCloud::kb*temperature
+       /mass
+    );
+
+for (molN = totalMols; molN < totalMols + totalZoneMols; molN++)
+{
+    // Assign velocity: random direction, magnitude determined by desired
+    // temperature
+
+    // Temperature gradients could be created by specifying a gradient in the
+    // zone subDict, or by reading a field from a mesh.
+
+    // The velocities are treated on a zone-by-zone basis for the purposes of
+    // removal of bulk momentum - hence nMols becomes totalZoneMols
+
+    velocity = (2.0*rand.vector01() - vector::one);
+
+    velocity *= initVelMag/mag(velocity);
+
+    momentumSum += mass*velocity;
+
+    initialVelocities.append(velocity);
+}