Experimental measurement of flow past cavities of different shapes

• Published in: Experimental thermal and fluid science Vol. 34; no. 5; pp. 505 - 515
• Main Authors: Ozalp, C., Pinarbasi, A., Sahin, B.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-07-2010; Elsevier
• Subjects: AMPLITUDES; CAVITIES; CIRCULAR CONFIGURATION; Corners; ENGINEERING; Exact sciences and technology; Flow past cavity; FLUCTUATIONS; Fluid dynamics; Fluid flow; Fundamental areas of phenomenology (including applications); GAS TURBINES; HEAT EXCHANGERS; Holes; Hydrodynamic stability; Instability of shear flows; Instrumentation for fluid dynamics; LAYERS; OSCILLATIONS; Physics; PIV; RECTANGULAR CONFIGURATION; REYNOLDS NUMBER; SHAPE; SHEAR; SPECTRA; STRESSES; THICKNESS; TRIANGULAR CONFIGURATION; TURBULENCE; Turbulence intensity; Turbulent flow; VELOCITY; VORTICES; Vorticity; WATER; Turbulence; Flow past cavity; PIV; Vorticity; Geometrical shape; Velocity distribution; Experimental study; Reynolds stress; Cavities; Measurement by laser beam; Wakes; Particle image velocimetry; Selfoscillation; Velocity measurement; Shear layer; Turbulence structure
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2009.11.003

Experiments are carried out in order to investigate the flow structure past a rectangular, triangular and semi-circular cavity of length-to-depth ratio of 2:1 using the Particle Image Velocimetry (PIV) technique. The experiments are performed in a large scale water channel with three different upstream velocities resulting in Reynolds numbers of 1230, 1460 and 1700, based on inflow momentum thickness, for each cavity type. Contours of constant averaged streamwise and transverse components of velocity, contours of constant averaged vorticity, Reynolds stress and streamline plots for each cavity type for the aforementioned three Reynolds numbers are presented. In addition, streamwise velocity, Reynolds stress and turbulence intensity values are compared for all cavity types. Effect of cavity shape on flow structure within the cavity is discussed in detail. Moreover, spectrum of instantaneous streamwise velocity fluctuations in shear layer near the downstream of the leading corner and the upstream of the trailing corner of the cavities are obtained and it was found that no organized oscillations are present in the flow; rectangular and triangular cavities have the largest amplitudes while semi-circular cavity has the smallest. Calculated turbulence intensities also reveal that the maximum turbulence intensities occur at cavity lid in the centerline section and rectangular and triangular cavities have larger turbulence intensity compared to semi-circular cavity.