Air Flow Analysis over a Hemisphere Attached on a Flat Surfacewith Thick Boundary Layer

Experimental and numerical analysis is performed to find wind flow behavior over a surface mounted hemisphere inside a channel in a thick boundary layer profile. The thick boundary layer profile is generated using a roughness element located at the entrance region of the channel. Hot-wire anemometer is used to measure air velocity and velocity fluctuation using Flow-Ware program. Knowing velocity fluctuation u’, the root-mean-square value of velocity is also calculated and the non-dimensional turbulence intensity is determined and plotted over the roof. For numerical simulation a three-dimensional RNG k-ε turbulence model is employed in order to calculate turbulent flow field similar to the experimental measurements. Results of hotwire measurements at the upstream are used as the inflow condition for the computational domain. Pressure and velocity distributions are presented at different locations in the plane of symmetry. Results of velocity profiles are compared with the experimental measurements at the several sections in the symmetry plane of the dome. Effect of thick boundary layer on the flow separation and recirculation over the hemisphere are demonstrated graphically and compared with the thin boundary layer results.

کلیدواژه ها:

Surface-Mounted Hemisphere ، Hot-Wire Anemometer ، Turbulent Flow ، CFD ، Flow Field