In the Viscous Model Dialog Box (p. 1903), under User-Defined Functions, select the appropriate UDFfrom the drop-down lists under Prandtl and Schmidt Numbers. Options include: TKE Prandtl Number,TDR Prandtl Number (- models only), SDR Prandtl Number (- model only), Energy PrandtlNumber, Wall Prandtl Number, and Turbulent Schmidt Number