Due to its wide industrial applications and complexity in its flow structure, the impinging get problem has always attracted the attention of many researchers in the experimental and computational fields of research. In the present thesis, the problem of rectangular turbulent jet impingement to a wall is investigated for various Reynolds numbers, while the distance between the jet and the wall is tenfold the width of the nozzle. In this study, we pursue two major goals. The first goal is to investigate the flow structures associated with a rectangular turbulent jet impinging a wall. Here, In order to study all the flow structures at different scales, we have employed a variety of computational and experimental techniques. The experimental techniques employed in this thesis include the tomographic Particle image velocimetry(Tomo-PIV), and the Laser Doppler Anemometry (LDA). Using a 3D tomographic velocimetry method for visualization of particles, which is proposed in this thesis for the first time for the problem of rectangular turbulent jet impingement to a wall, turbulent structures of the flow is investigated through 3D tomographic POD method, and the energy percentage of each turbulent structure out of the total turbulent energy is determined. Using the available 3D flow data and high resolution flow field, flow structures that had received less attention previously are investigated for the impingement area as well as other flow zones. Moreover, instantaneous and average eddy structures of the flow are examined through three criteria including ? , Q and ? 2 criteria. Subsequently, using LDA, small scale structures of the flow are investigated for three Reynolds numbers of 3000, 6000, and 9000, and the effect of the Reynolds number on dimensionless average velocity and dimensionless Reynolds stress is studied. Also, the challenges regarding post-processing of data related to this experimental method is identified, and some methodologies for elimination of the existing errors are scrutinized. In addition, various length scales of the turbulent flow are extracted, and the data is used for calculating the computational mesh in the large eddy simulation (LES) method. The second goal of the present project is assessment of the validity of various turbulence models. For this purpose, five different models based on averaged Navies-Stokes equations have been used. These models which include, k- ? , k-? RNG, k-? SST RSM and v 2 f are amongst the most widely used turbulence models applied for simulation of industrial case studies. In fact, in this section of the thesis we aim at comparing the simulation results obtained from these models and our measured experimental data to determine the accuracy and error related to each of those turbulence models. Our results revealed that compared with other averaging models, the simulation data obtained from the v 2 f model is more consistent with the experimental data especially in the vicinity of the centreline of the jet. Moreover, the one-equation subgrid-scale model and local dynamic Smagorinsky model are used in the LES model, and the results are compared with the experimental data. From the results, it was found that the local dynamic Smagorinsky method has a very good prediction of the flow field in most of the flow regions. Hence, instantaneous flow structures are investigated using this method and the results are compared with the experimental data from LDA and PIV. It is worth mentioning that despite most of the previous studies, in our research, the same exact initial and boundary conditions are applied for the computational and experimental procedures, which enables a valid comparison between the results from the two approaches Keywords: Turbulent Impining Jet, Laser Doppler Anemometry, Particle Image Velocimetry, Reynolds-averaged Navier-Stokes models, Large Eddy Simulation