順圧力勾配下に発達する乱流境界層の外層における構造

抄録

Effect of favorable pressure gradient on the similarity in the turbulent boundary layer has been investigated experimentally. In an equilibrium turbulent boundary layer under favorable pressure gradient, mean velocity, Reynolds stresses and wall shear stress were measured and compared with similarities as seen in flat plate boundary layers. The logarithmic mean velocity profile holds in the inner layer under the favorable pressure gradient. Otherwise, the wake component in the outer layer disappears due to the favorable pressure gradient. Turbulent kinematic energy budget is evaluated and compared for zero and favorable pressure gradients. The production and dissipation are almost balanced in the inner layer under zero and favorable pressure gradients. However, the production, dissipation and diffusion terms are reduced in magnitude under favorable pressure gradient. In the intermittency of the turbulent-nonturbulent interface, turbulent region seems to be enlarged due to favorable pressure gradient.