Scale effects on turbulent boundary layer development and flow separation around V/STOL inlets at high incidence

1981 ◽  
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Flow Separation ◽  
Scale Effects ◽  
Boundary Layer Development ◽  
High Incidence ◽  
Layer Development

Prediction of Turbulent Boundary Layer Development in Conical Diffusers

1966 ◽  
Vol 8 (4) ◽  
pp. 426-436 ◽  
Author(s):  
A. D. Carmichael ◽  
G. N. Pustintsev
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Shape Factor ◽  
Turbulent Boundary Layers ◽  
Energy Deficit ◽  
Momentum Thickness ◽  
Boundary Layer Development ◽  
Layer Development

Methods of predicting the growth of turbulent boundary layers in conical diffusers using the kinetic-energy deficit equation were developed. Three different forms of auxiliary equations were used. Comparison between the measured and predicted results showed that there was fair agreement although there was a tendency to underestimate the predicted momentum thickness and over-estimate the predicted shape factor.

Flow Separation and Performance of Decelerating Channels for Centrifugal Turbomachines

1975 ◽  
Vol 97 (3) ◽  
pp. 388-394 ◽  
Author(s):  
Teruo Sakurai
Keyword(s):  
Boundary Layer ◽  
Flow Separation ◽  
Pressure Rise ◽  
Logarithmic Spiral ◽  
Performance Pressure ◽  
Boundary Layer Development ◽  
And Performance ◽  
Layer Development

Fundamental studies on diffusers were performed in order to get a better knowledge of flow in centrifugal turbomachines and to improve their performance. First, the flow inside channels with logarithmic spiral walls was investigated. Boundary layer development and its effect on the diffuser performance (pressure-rise and its efficiency) were analyzed. Effects of diffuser configurations in circular cascades were also made clear. Further, separation in impellers with logarithmic spiral blades was computed and discussed.

scholarly journals Effect of turbulence on the wake of a wall-mounted cube

2016 ◽  
Vol 804 ◽  
pp. 513-530 ◽  
Author(s):  
R. Jason Hearst ◽  
Guillaume Gomit ◽  
Bharathram Ganapathisubramani
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Turbulence Intensity ◽  
Free Stream ◽  
Reattachment Length ◽  
Free Stream Turbulence ◽  
Boundary Layer Development ◽  
Image Velocimetry ◽  
Shedding Frequency ◽  
Layer Development

The influence of turbulence on the flow around a wall-mounted cube immersed in a turbulent boundary layer is investigated experimentally with particle image velocimetry and hot-wire anemometry. Free-stream turbulence is used to generate turbulent boundary layer profiles where the normalised shear at the cube height is fixed, but the turbulence intensity at the cube height is adjustable. The free-stream turbulence is generated with an active grid and the turbulent boundary layer is formed on an artificial floor in a wind tunnel. The boundary layer development Reynolds number ($Re_{x}$) and the ratio of the cube height ($h$) to the boundary layer thickness ($\unicode[STIX]{x1D6FF}$) are held constant at $Re_{x}=1.8\times 10^{6}$ and $h/\unicode[STIX]{x1D6FF}=0.47$. It is demonstrated that the stagnation point on the upstream side of the cube and the reattachment length in the wake of the cube are independent of the incoming profile for the conditions investigated here. In contrast, the wake length monotonically decreases for increasing turbulence intensity but fixed normalised shear – both quantities measured at the cube height. The wake shortening is a result of heightened turbulence levels promoting wake recovery from high local velocities and the reduction in strength of a dominant shedding frequency.

Research on Turbulent Boundary Layer Development of Hydraulic Jump Region with the Theory of Plane Adhesive Wall Jet Flow

2012 ◽  
Vol 212-213 ◽  
pp. 1141-1146
Author(s):  
Zhi Chang Zhang ◽  
Ruo Bing Li ◽  
Ying Zhao ◽  
Ming Huan Fu
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Hydraulic Jump ◽  
Rectangular Channel ◽  
Jet Flow ◽  
Wall Jet ◽  
Boundary Layer Development ◽  
Wall Jet Flow ◽  
Momentum Integral ◽  
Layer Development

【Objective】The calculation of turbulent boundary layer development in hydraulic jump region is put forwarded.【Method】According to the analysis of predecessors’ researches about plane adhesive wall jet flow of rectangular channel, Based on the momentum integral equation of turbulent boundary layer and the velocity distribution formula of adhesive wall jet flow, turbulent boundary layer development of hydraulic jump region in rectangular channel is researched.【Result】Formulas of the development of boundary layer in hydraulic jump region and drag coefficient are obtained, the accuracy of equations are verified by the example. 【Conclusion】The calculation has enlightened effect on the hydraulic characteristics of hydraulic jump.

Flow in a deep turbulent boundary layer over a surface distorted by water waves

1972 ◽  
Vol 55 (4) ◽  
pp. 719-735 ◽  
Author(s):  
A. A. Townsend
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Phase Velocity ◽  
Surface Stress ◽  
Water Waves ◽  
Turbulent Energy ◽  
Mean Flow ◽  
Boundary Layer Development ◽  
The Mean ◽  
Layer Development

Linearized equations for the mean flow and for the turbulent stresses over sinusoidal, travelling surface waves are derived using assumptions similar to those used by Bradshaw, Ferriss & Atwell (1967) to compute boundary-layer development. With the assumptions, the effects on the local turbulent stresses of advectal, vertical transport, generation and dissipation of turbulent energy can be assessed, and solutions of the equations are expected to resemble closely real flows with the same conditions. The calculated distributions of surface pressure indicate rates of wave growth (expressed as fractional energy gain during a radian advance of phase) of about 15(ρa/ρw) (τo/c2), where τo is the surface stress, co the phase velocity and ρa and ρw the densities of air and water, unless the wind velocity at height λ/2π is less than the phase velocity. The rates are considerably less than those measured by Snyder & Cox (1966), by Barnett & Wilkerson (1967) and by Dobson (1971), and arguments are presented to show that the linear approximation fails for wave slopes of order 0.1.

Curved Diffusing Annulus Turbulent Boundary-Layer Development

1972 ◽  
Vol 9 (2) ◽  
pp. 97-98 ◽  
Author(s):  
SHOICHI FUJII ◽  
THEODORE H. OKIISHI
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Development ◽  
Layer Development

Shock-boundary layer interaction and transition modelling in turbomachinery flows

1997 ◽  
Vol 211 (3) ◽  
pp. 225-234 ◽  
Author(s):  
V Michelassi
Keyword(s):  
Boundary Layer ◽  
Turbine Blade ◽  
Turbulence Model ◽  
Flow Separation ◽  
Good Description ◽  
Suction Side ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Boundary Layer Development ◽  
Layer Development

The transonic turbulent compressible flow in channels and turbine linear cascades is computed by using a Navier-Stokes solver. Turbulence effects are simulated by means of the k-ω turbulence model. A realiability constraint is introduced to improve the turbulence model performances and stability in the presence of stagnation points. In both the flow over the bump and the turbine blade, the shock induces a flow separation that affects the boundary layer development. In both cases the proposed model succeeds in predicting the flow separation. For the flow over the turbine blade a simple transition model based on integral parameters is introduced to mimic the effect of the boundary layer transition across the shock wave on the suction side. Relaminarization is also properly predicted on the pressure side, thereby allowing a good description of the boundary layer development and shock pattern.

Sign in / Sign up

Export Citation Format

Share Document