CALCULATION OF IMPINGING-JET HEAT-TRANSFER WITH THE LOW-REYNOLDS-NUMBER Q-ZETA TURBULENCE MODEL

A two-equation model of turbulent heat transfer has been devised along the lines of the successful q-zeta model of the turbulent velocity fi eld. The new variables are the square root of the temperature variance and its dissipation rate. These variables are attractive for eddy-dif fusivity calculations, because their variation with distance y from th e wall is linear in y when y --> O. This feature in the q-zeta model f or the eddy-viscosity leads to economical computations of good accurac y. The new heat transfer model has been calibrated with data from chan nel and boundary-layer flows and is applied here to the computation of heat transfer in the stagnation region of an impinging jet. The resul ts compare very favourably with those based upon the assumption of a c onstant turbulent Prandtl number. This quantity is obtained as an outp ut from the calculations instead of being an input to them. (C) 1997 b y Elsevier Science Inc.