kOmega2006: New RAS turbulence model

This is the 2006 version of Wilcox's k-omega RAS turbulence model which has some
similarities in formulation and behaviour to the k-omega-SST model but is much
simpler and cleaner.  This model is likely to perform just as well as the
k-omega-SST model for a wide range of engineering cases.

Description
    Standard (2006) high Reynolds-number k-omega turbulence model for
    incompressible and compressible flows.

    References:
    \verbatim
        Wilcox, D. C. (2006).
        Turbulence modeling for CFD, 3rd edition
        La Canada, CA: DCW industries, Inc.

        Wilcox, D. C. (2008).
        Formulation of the kw turbulence model revisited.
        AIAA journal, 46(11), 2823-2838.
    \endverbatim

    The default model coefficients are
    \verbatim
        kOmega2006Coeffs
        {
            Cmu         0.09;
            beta0       0.0708;
            gamma       0.52;
            Clim        0.875;
            alphak      0.6;
            alphaOmega  0.5;
        }
    \endverbatim

tutorials/incompressible/simpleFoam/pitzDaily/constant/momentumTransport

@@ -18,7 +18,7 @@ simulationType RAS;
 
 RAS
 {
-    // Tested with kEpsilon, realizableKE, kOmega, kOmegaSST, v2f,
+    // Tested with kEpsilon, realizableKE, kOmega, kOmega2006, kOmegaSST, v2f,
     // ShihQuadraticKE, LienCubicKE.
     model           kEpsilon;