Extended Velocity–Enthalpy Relations for Wall-Bounded and Free Shear Layers

2005 ◽  
Vol 127 (6) ◽  
pp. 1205-1209 ◽  
Author(s):  
B. W. van Oudheusden
Keyword(s):  
Shear Flow ◽  
Prandtl Number ◽  
Shear Layers ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Total Enthalpy ◽  
Rational Extension ◽  
Free Shear Layers ◽  
Steady Shear Flow ◽  
The Subject

The relation between the velocity and the enthalpy in steady shear flow is expressed by the Crocco–Busemann relation, which states that for adiabatic conditions the total enthalpy remains constant throughout the shear layer when the Prandtl number is one. The subject of the present Technical Brief is the rational extension of this concept in case the Prandtl number differs from one. The comparison between wall-bounded and free shear flows is studied in particular, as well as the possible application of the concept in turbulent shear flow.

Turbulent shear flow over active and passive porous surfaces

2001 ◽  
Vol 442 ◽  
pp. 89-117 ◽  
Author(s):  
JAVIER JIMÉNEZ ◽  
MARKUS UHLMANN ◽  
ALFREDO PINELLI ◽  
GENTA KAWAHARA
Keyword(s):  
Shear Flow ◽  
Pressure Fluctuations ◽  
Shear Layers ◽  
Linear Instability ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Flow Mechanism ◽  
Helmholtz Instability ◽  
Local Pressure ◽  
The Mean

The behaviour of turbulent shear flow over a mass-neutral permeable wall is studied numerically. The transpiration is assumed to be proportional to the local pressure fluctuations. It is first shown that the friction coefficient increases by up to 40% over passively porous walls, even for relatively small porosities. This is associated with the presence of large spanwise rollers, originating from a linear instability which is related both to the Kelvin–Helmholtz instability of shear layers, and to the neutral inviscid shear waves of the mean turbulent profile. It is shown that the rollers can be forced by patterned active transpiration through the wall, also leading to a large increase in friction when the phase velocity of the forcing resonates with the linear eigenfunctions mentioned above. Phase-lock averaging of the forced solutions is used to further clarify the flow mechanism. This study is motivated by the control of separation in boundary layers.

Turbulent Shear Flow Over Surface Mounted Obstacles

1990 ◽  
Vol 112 (4) ◽  
pp. 376-385 ◽  
Author(s):  
W. H. Schofield ◽  
E. Logan
Keyword(s):  
Shear Flow ◽  
Shear Layers ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Mean Flow ◽  
Wide Range ◽  
Flow Features ◽  
Model Geometry ◽  
The Mean ◽  
High Reynolds

The mean flow field surrounding obstacles attached to a wall under a turbulent boundary layer is analyzed. The analysis concentrates on how major features of the flow are influenced by model geometry and the incident shear flow. Experimental data are analyzed in terms of nondimensionalized variables chosen on the basis that their effect on major flow features can be simply appreciated. The data are restricted to high Reynolds number shear layers thicker than the attached obstacle. The work shows that data from a wide range of flows can be collapsed if appropriate nondimensional scales are used.

Open-loop control of compensation for optical propagation through a turbulent shear flow

1998 ◽  
Author(s):  
C. Truman ◽  
Lenore McMackin ◽  
Robert Pierson ◽  
Kenneth Bishop ◽  
Ellen Chen
Keyword(s):  
Shear Flow ◽  
Open Loop ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Open Loop Control ◽  
Loop Control ◽  
Optical Propagation

scholarly journals Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

2016 ◽  
Vol 1 (6) ◽  
Author(s):  
D. Fiscaletti ◽  
G. E. Elsinga ◽  
A. Attili ◽  
F. Bisetti ◽  
O. R. H. Buxton
Keyword(s):  
Shear Flow ◽  
Strain Rate ◽  
Scale Dependence ◽  
Turbulent Shear ◽  
Turbulent Shear Flow

The structure of turbulent shear flow

1980 ◽  
Vol 70 (1-2) ◽  
pp. 187-188
Author(s):  
F.H. Busse
Keyword(s):  
Shear Flow ◽  
Turbulent Shear ◽  
Turbulent Shear Flow

Effects of turbulent shear flow on zooplankton distribution

1990 ◽  
Vol 37 (3) ◽  
pp. 447-461 ◽  
Author(s):  
Loren R. Haury ◽  
Hidekatsu Yamazaki ◽  
Eric C. Itsweire
Keyword(s):  
Shear Flow ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Zooplankton Distribution

scholarly journals MAGNETIC RESONANCE SIGNAL LOSS IN TURBULENT SHEAR FLOW

2002 ◽  
Vol 14 (01) ◽  
pp. 1-11
Author(s):  
LIANG-DER JOU
Keyword(s):  
Shear Flow ◽  
Velocity Fluctuation ◽  
Phase Fluctuation ◽  
Eddy Diffusivity ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Signal Loss ◽  
Flow Shear ◽  
Magnetic Gradient ◽  
Spin Echo Sequence

NMR signal loss due to turbulent shear flow is discussed, and a general expression for the phase fluctuation is derived. In the presence of flow shear, the velocity fluctuation perpendicular to the direction of magnetic gradient and the Reynolds stress can cause loss of MR signal Most of signal loss results from the boundary layer, where the flow shear is strong in turbulent pipe flaw, Half the signal loss within the mixing layer distal to a moderate stenosis is caused by the velocity fluctuation in the direction of magnetic gradient, while the remaining results from the velocity, fluctuation perpendicular to the magnetic gradient. The use of eddy diffusivity for the description of signal dephasing in a spin echo sequence is also addressed; A positive, constant eddy diffusivity can not describe the temporal change of phase fluctuation correctly.

Sign in / Sign up

Export Citation Format

Share Document