Journal of the Faculty of Engineering and Architecture of Gazi University 36:2 (2021) 627-640 Experimental and numerical investigation of effects of different cavity geometries on flow in a rectangular channel Yücel Özmen 1 * , Erhan Aksu 2 , Nurhan Gürsel Özmen 1 1 Mechanical Engineering, Karadeniz Technical University, Trabzon, 61080, Turkey 2 Naval Architecture and Marine Engineering, Karadeniz Technical University, Trabzon, 61530, Turkey Highlights: Graphical/Tabular Abstract  The effect of changing in cavity geometry to the flow field  Pressure distributions along the cavity surfaces  Mean velocity and turbulence kinetic energy analysis in the cavities Cavity flow is a fundamental problem in fluid mechanics. Flow over a cavity is a complex phenomenon due to there usually being strong pressure, velocity and density fluctuations. These in turn can lead to increased drag forces, excessive noise and vibrations problems in structures. It is therefore essential to understand the cavity flow physics. In this study, the effect of changing in cavity geometry to the flow field was investigated experimentally and numerically. In four different cavity geometries, triangular, trapezoid, rectangular and inverted trapezoid, pressure distributions along the cavity surfaces through the flow direction and mean velocity and turbulence kinetic energy distributions along the cavities were obtained. Figure A. Pressure coefficients in trapezoid cavity geometry Purpose: The aim of the study is to investigate the effect of change in cavity geometry on flow field. Theory and Methods: The effect of changing in cavity geometry to the flow field was investigated experimentally and numerically. In four different cavity geometries, triangular, trapezoid, rectangular and inverted trapezoid, pressure distributions along the cavity surfaces through the flow direction and mean velocity and turbulence kinetic energy distributions along the cavities were obtained. Realizable k-ε and Reynolds Stress turbulence models were used for time-independent three-dimensional numerical solutions. Results: The results obtained for Re=100,000 show that both pressure distributions and velocity distributions are affected from the cavity geometry. Flow separating from the front edge of the cavities forms reverse flow regions in the cavities. For triangular and trapezoidal geometries, the pressure coefficients along the cavity surfaces show a sinusoidal distribution. For rectangular and inverted trapezoidal geometries, the pressure coefficients at the center of the cavity bases have negative peak values. Turbulence kinetic energy increases between the free flow and the reverse flow regions. Conclusion: It was concluded that Reynolds Stress turbulence model results are closer to the experimental data. Keywords:  Cavity flow  Pressure coefficient  Mean velocity  Turbulence kinetic energy  Turbulence modelling Article Info: Research Article Received: 24.05.2019 Accepted: 29.09.2020 DOI: 10.17341/gazimmfd.569773 Correspondence: Author: Yücel Özmen e-mail: yozmen@ktu.edu.tr phone: +90 462 377 3576