流体理论中平板湍流边界层表面摩擦系数(skin friction coefficient)近似估计公式总结

流体理论中的平板湍流边界层表面摩擦系数(skin friction coefficient)近似估计公式总结

流体中的表面摩擦系数(skin friction coefficient, C f C_f Cf)可以定义为:
C f ≡ τ w 1 2   ρ   U ∞ 2 C_f \equiv \frac{\tau_w}{\frac{1}{2} \, \rho \, U_\infty^2} Cf21ρU2τw
其中, τ w \tau_w τw表示局部壁剪切应力(wall shear stress), ρ \rho ρ是流体密度。 U ∞ U_\infty U是自由流速度(free-stream velocity),通常在边界层外或入口处取。
关于一个平板湍流边界层的几种局部表面摩擦近似公式如下:

(1) 1/7 power law:

C f = 0.0576 R e x − 1 / 5 f o r 5 ⋅ 1 0 5 < R e x < 1 0 7 C_f = 0.0576 Re_x^{-1/5} \quad {for} \quad 5 \cdot 10^5 < Re_x < 10^7 Cf=0.0576Rex1/5for5105<Rex<107

(2) 带有实验校正的1/7 power law (见文献[3]式 21.12):

C f = 0.0592   R e x − 1 / 5 f o r 5 ⋅ 1 0 5 < R e x < 1 0 7 C_f = 0.0592 \, Re_x^{-1/5} \quad {for} \quad 5 \cdot 10^5 < Re_x < 10^7 Cf=0.0592Rex1/5for5105<Rex<107

(3)Schlichting(见文献[3]中式21.16的脚注)

C f = [ 2   l o g 10 ( R e x ) − 0.65 ] − 2.3 f o r R e x < 1 0 9 C_f = [ 2 \, log_{10}(Re_x) - 0.65 ] ^{-2.3} \quad {for} \quad Re_x < 10^9 Cf=[2log10(Rex)0.65]2.3forRex<109

(4)Schultz-Grunov (见文献[3]式 21.19a):

C f = 0.370   [ l o g 10 ( R e x ) ] − 2.584 C_f = 0.370 \, [ log_{10}(Re_x) ]^{-2.584} Cf=0.370[log10(Rex)]2.584

(文献[1]式(38)):

1.0 / C f 1 / 2 = 1.7 + 4.15   l o g 10 ( R e x   C f ) 1.0/C_f^{1/2} = 1.7 + 4.15 \, log_{10} (Re_x \, C_f) 1.0/Cf1/2=1.7+4.15log10(RexCf)

下面是从文献[2],p19页中获取的表面摩擦公式,可以适当参考:

(5)Prandtl (1927):

C f = 0.074   R e x − 1 / 5 C_f = 0.074 \, Re_x^{-1/5} Cf=0.074Rex1/5

(6)Telfer (1927):

C f = 0.34   R e x − 1 / 3 + 0.0012 C_f = 0.34 \, Re_x^{-1/3} + 0.0012 Cf=0.34Rex1/3+0.0012

(7) Prandtl-Schlichting (1932):

C f = 0.455   [ l o g 10 ( R e x ) ] − 2.58 C_f = 0.455 \, [ log_{10}(Re_x)]^{-2.58} Cf=0.455[log10(Rex)]2.58

(8) Schoenherr (1932):

C f = 0.0586   [ l o g 10 ( R e x   C f ) ] − 2 C_f = 0.0586 \, [ log_{10}(Re_x \, C_f )]^{-2} Cf=0.0586[log10(RexCf)]2

(9) Schultz-Grunov (1940):

C f = 0.427   [ l o g 10 ( R e x ) − 0.407 ] − 2.64 C_f = 0.427 \, [ log_{10}(Re_x) - 0.407]^{-2.64} Cf=0.427[log10(Rex)0.407]2.64

(10) Kempf-Karman (1951):

C f = 0.055   R e x − 0.182 C_f = 0.055 \, Re_x^{-0.182} Cf=0.055Rex0.182

(11) Lap-Troost (1952):

C f = 0.0648   [ l o g 10 ( R e x   C f 0.5 ) − 0.9526 ] − 2 C_f = 0.0648 \, [log_{10}(Re_x \, C_f^{0.5})-0.9526]^{-2} Cf=0.0648[log10(RexCf0.5)0.9526]2

(12)Landweber (1953):

C f = 0.0816   [ l o g 10 ( R e x ) − 1.703 ] − 2 C_f = 0.0816 \, [log_{10}(Re_x) - 1.703]^{-2} Cf=0.0816[log10(Rex)1.703]2

(13 )Hughes (1954):

C f = 0.067   [ l o g 10 ( R e x ) − 2 ] − 2 C_f = 0.067 \, [log_{10}(Re_x) - 2 ] ^{-2} Cf=0.067[log10(Rex)2]2

(14) Wieghard (1955):

C f = 0.52   [ l o g 10 ( R e x ) ] − 2.685 C_f = 0.52 \, [log_{10}(Re_x)] ^{-2.685} Cf=0.52[log10(Rex)]2.685

(15)ITTC (1957):

C f = 0.075   [ l o g 10 ( R e x ) − 2 ] − 2 C_f = 0.075 \, [log_{10}(Re_x) - 2 ] ^{-2} Cf=0.075[log10(Rex)2]2

(16)Gadd (1967):

C f = 0.0113   [ l o g 10 ( R e x ) − 3.7 ] − 1.15 C_f = 0.0113 \, [log_{10}(Re_x) - 3.7 ] ^{-1.15} Cf=0.0113[log10(Rex)3.7]1.15

(17) Granville (1977):

C f = 0.0776   [ l o g 10 ( R e x ) − 1.88 ] − 2 + 60   R e x − 1 C_f = 0.0776 \, [log_{10}(Re_x) - 1.88 ] ^{-2} + 60 \, Re_x^{-1} Cf=0.0776[log10(Rex)1.88]2+60Rex1

(18) Date Turnock (1999):

C f = [ 4.06   l o g 10 ( R e x   C f ) − 0.729 ] − 2 C_f = [4.06 \, log_{10}(Re_x \, C_f) - 0.729]^{-2} Cf=[4.06log10(RexCf)0.729]2

参考文献

[1] von Karman, Theodore (1934), “Turbulence and Skin Friction”, J. of the Aeronautical Sciences, Vol. 1, No 1, 1934, pp. 1-20.
[2] Lazauskas, Leo Victor (2005), “Hydrodynamics of Advanced High-Speed Sealift Vessels”, Master Thesis, University of Adelaide, Australia (download).
[3] Schlichting, Hermann (1979), Boundary Layer Theory, ISBN 0-07-055334-3, 7th Edition.

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