U.P.B. Sci. Bull., Series D, Vol. 76, Iss. 2, 2014 ISSN 1454-2358 NUMERICAL PREDICTION OF WALL SHEAR RATE IN IMPINGING CROSS-SHAPED JET AT MODERATE REYNOLDS NUMBER Florin BODE 1,2 , Kodjovi SODJAVI 3 , Amina MESLEM 3 , Ilinca NASTASE 2 A Computational Fluid Dynamics investigation of impinging lobed jet issuing from a cruciform orifice nozzle was conducted at moderate Reynolds number of 5290, based on the equivalent diameter of the nozzle (De=7.64 mm) and the streamwise bulk velocity (U 0 =0.72 m/s). The wall shear rate obtained from numerical simulation is compared to the one acquired experimentally using electro- diffusion technique [1]. The best results were obtained by k-ω based turbulence models. The model with the best accuracy for the present work was k-ω SST, which was the only model that has managed to capture the inflection point on the radial distribution of wall shear rate. Keywords: impinging jet, numerical simulation, wall shear rate 1. Introduction Impinging jets have received considerable attention given their many applications connected to the enhancement of mass or heat transfer including industrial processes (paper drying, cooling of heated components of turbine engines and of combustion chambers, cooling of electronic equipments, processing of some metals and glass, deicing of aircraft systems, drying of textile, food products, films and papers, etc [2, 3]). Another type of application is the microenvironment control in personalized ventilation in buildings or vehicles [4]. While for the former, the jet exit Reynolds number falls in general in high or moderate values ( > 5000), for the latter, the Reynolds number is low or moderate (from few hundred up to few thousands). The main objective of this study was to assess the global capability of different turbulence models to capture the flow behaviour in the case of a lobed cross shaped orifice impinging jet. The article presents results issued from a series of experimental and numerical investigations on circular and lobed impinging jets at low and moderate Reynolds numbers including our previous papers [1, 5]. 1 Technical University of Cluj-Napoca , florin.bode@termo.utcluj.ro 2 Technical University of Civil Engineering in Bucharest, Research Center CAMBI, ilinca.nastase@cambi.ro - corresponding author 3 University of La Rochelle, LaSIE Laboratory, ameslem@univ-lr.fr