高レイノルズ数乱流境界層における平均速度分布の普遍性（諸外国の大型風洞との比較）

抄録

High Reynolds number turbulent boundary layer measurement is performed in the RTRI ’s low-noise wind tunnel in Maibara Japan. The momentum thickness Reynolds number R_θ is up to approximately 8×10⁴. Mean velocity statistics are compared with those of large wind tunnel facilities in Melbourne, Sweden, New Hampshire, Netherland, France and UK. The ratio of momentum thickness θ，displacement thickness δ_* and Rotta-Clauser thickness Δ against the boundary layer thickness δ₉₉ does not show the similar trend but depends on the facility. Mena velocity profile is approximated by the log-law relations; U⁺ = 1/κ ∙ ln(y⁺) + B + Π/κ ∙ W(y/δ_c) and (U₀ − U)/u_τ = − 1/κ ∙ ln(y/Δ) + B₁ , where W is wake function, U₀ is free stream velocity, u_τ is friction velocity, and δ_c is Coles’ boundary layer thickness. Parameters κ，B, B₁, and Π distribute in wide range, but they relate with one another and the simple relation between κ and B is presented. Also the relation between κB₁ and Π is confirmed. When the effect of virtual origin is corrected, the Reynolds number R_x′ ≡ U₀x′/ν , where x′ = x + x₀, x is the distance from the leading edge and x₀ is virtual origin, indicates the same trend against R_θ independent of facilities. Also, the skin friction coefficients agree with one another as a function of Reynolds number based on displacement thickness.