In this study, impingement air jet heat and flow characteristics of hexagonal finned heat sink which was named as OHS-2 were determined experimentally and analysed numerically by Ansys-Fluent CFD programme. The heat sink was optimized by using Taguchi method in the wind tunnel according to L-18(2(1)x3(7)) orthogonal array in earlier study . Therefore, the optimized heat sink was used instead of another heat sink. Six of most commonly used turbulence models in the numerical analysis of heat and mass transfer with impinging jets were examined and k-epsilon reliable turbulence model was chosen the most suitable for experimental study. The experimental and numerical studies were carried out for a heat sink with a nozzle diameter, two different Y/d distances, 6 different flow rates and 3 different fin heights. The variations of the Nu-Re and Cp-x,Cp-y-l/(l(0)/2) were analysed and compared. Finally, heat transfer correlations were produced from experimental and numerical results of impingement jet heat transfer. Also the numerical and experimental results were observed to be in a good agreement. (C) 2016 The Authors. Published by Elsevier Ltd.