scholarly journals Wall Temperature Effects on the Reynold Stress of Flat-Plate Turbulent Boundary Layer: a Numerical Investigation

2019 ◽  
Vol 11 (3) ◽  
pp. 653-663 ◽  
Author(s):  
Xin Li
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Flat Plate ◽  
Numerical Investigation ◽  
Wall Temperature ◽  
Temperature Effects

Wall Temperature and Prandtl Number Effects on Turbulent Boundary Layer Thicknesses and Shape Factors for Subsonic Compressible Gas Flow Over a Flat Plate

1969 ◽  
Author(s):  
W. J. Kelnhofer
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Prandtl Number ◽  
Flat Plate ◽  
Wall Temperature ◽  
Gas Flow ◽  
Density Variation ◽  
Shape Factors ◽  
Heating And Cooling ◽  
Subsonic Gas Flow

Based on n-power velocity and temperature profiles a method of computing various turbulent boundary layer thicknesses and shape factors affected by wall temperature and Prandtl number for fully developed subsonic gas flow over a flat plate is presented. Density variation in the boundary layer is given main consideration. Numerical computations include both heating and cooling of gas. Boundary layer thicknesses and shape factors are shown to be significantly affected by wall temperature and to a lesser degree by Prandtl number. An experiment is described which involved air flow up to 30 m/sec over a flat plate maintained at constant wall temperatures up to 250 C. Comparisons between theory and experiment are good.

scholarly journals Direct Numerical Simulation on Mach Number and Wall Temperature Effects in the Turbulent Flows of Flat-Plate Boundary Layer

2014 ◽  
Vol 17 (1) ◽  
pp. 189-212 ◽  
Author(s):  
Xian Liang ◽  
Xinliang Li
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Direct Numerical Simulation ◽  
Flat Plate ◽  
Wall Temperature ◽  
Wall Region ◽  
Mean Velocity ◽  
Reynolds Analogy

AbstractIn this paper, direct numerical simulation (DNS) is presented for spatially evolving turbulent boundary layer over an isothermal flat-plate atMa∞= 2.25,5,6,8. WhenMa∞= 8, two cases with the ratio of wall-to-reference temperatureTω/T∞= 1.9 and 10.03 are considered respectively. The wall temperature approaches recovery temperatures for other cases. The characteristics of compressible turbulent boundary layer (CTBL) affected by freestream Mach number and wall temperature are investigated. It focuses on assessing compressibility effects and the validity of Morkovin's hypothesis through computing and analyzing the mean velocity profile, turbulent intensity, the strong Reynolds analogy (SRA) and possibility density function of dilatation term. The results show that, when the wall temperature approaches recovery temperature, the effects of Mach number on compressibility is insignificant. As a result, the compressibility effect is very weak and the Morkovin's hypothesis is still valid for Mach number even up to 8. However, when Mach number equal to 8, the wall temperature effect on the compressibility is sensitive. In this case, whenTω/T∞= 1.9, the Morkovin's hypothesis is not fully valid. The validity of classical SRA depends on wall temperature directly. A new modified SRA is proposed to eliminate such negative factor in near wall region. Finally the effects of Mach number and wall temperature on streaks are also studied.

Wall Temperature and Prandtl Number Effects on Turbulent Boundary Layer Thicknesses and Shape Factors for Subsonic Compressible Gas Flow Over a Flat Plate

1969 ◽  
Vol 91 (4) ◽  
pp. 281-289
Author(s):  
W. J. Kelnhofer
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Prandtl Number ◽  
Flat Plate ◽  
Wall Temperature ◽  
Gas Flow ◽  
Density Variation ◽  
Shape Factors ◽  
Heating And Cooling ◽  
Subsonic Gas Flow

Based on n-power velocity and temperature profiles a method of computing various turbulent boundary layer thicknesses and shape factors affected by wall temperature and Prandtl number for fully developed subsonic gas flow over a flat plate is presented. Density variation in the boundary layer is given main consideration. Numerical computations include both heating and cooling of the gas. Boundary layer thicknesses and shape factors are shown to be significantly affected by wall temperature and to a lesser degree by Prandtl number. An experiment is described which involved air flow up to 30 m/sec over a flat plate maintained at constant wall temperatures up to 250 C. Comparisons between theory and experiment are good.

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