Experimental investigation of the influence of buoyancy on turbulent flow adjacent to a horizontal plate induced by a trip wire

• Published in: International journal of thermal sciences 2003-11, Vol.42 (11), p.1013-1020
• Main Author: Abu-Mulaweh, H.I.
• Format: Article
• Language: English
• Subjects: Boundary layer and shear turbulence; Convection and heat transfer; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Physics; Turbulent flows, convection, and heat transfer
• ISSN: 1290-0729; 1778-4166
• DOI: 10.1016/S1290-0729(03)00078-4

The effects of buoyancy force on fully developed turbulent mixed convective boundary layer flow over a horizontal heated flat plate are studied experimentally. A 4-mm trip wire, placed 10 cm from the leading edge of the plate, was used for accelerating the flow transition from laminar to turbulent. Measurements of the flow field were carried out at two streamwise locations ( x=125 and 150 cm), for two free stream velocities of u ∞=1.15 and 2 m·s −1, and four different temperature differences between the heated surface and the free stream air: Δ T=0 °C (i.e., forced convection) and Δ T=15,30, and 53 °C (i.e., mixed convection) by using a laser-Doppler velocimeter. The measured results are compared with results from turbulent flow theory. The results revealed, as expected, the trip wire did accelerate the transition of laminar boundary layer flow to a fully developed turbulent boundary layer flow. Also, it was found that the buoyancy force resulting from wall heating has negligible effect on the flow field as long as the flow is stable because the buoyancy force has no streamwise component