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Properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows
 J. Fluid Mech
, 2004
"... The properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows are explored both experimentally and theoretically. Available highquality data reveal a dynamically relevant fourlayer description that is a departure from the mean profile fourlayer description tradit ..."
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Cited by 20 (9 self)
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The properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows are explored both experimentally and theoretically. Available highquality data reveal a dynamically relevant fourlayer description that is a departure from the mean profile fourlayer description traditionally and nearly universally ascribed to turbulent wall flows. Each of the four layers is characterized by a predominance of two of the three terms in the governing equations, and thus the mean dynamics of these four layers are unambiguously defined. The inner normalized physical extent of three of the layers exhibits significant Reynoldsnumber dependence. The scaling properties of these layer thicknesses are determined. Particular significance is attached to the viscous/Reynoldsstressgradient balance layer since its thickness defines a required length scale. Multiscale analysis (necessarily incomplete) substantiates the fourlayer structure in developed turbulent channel flow. In particular, the analysis verifies the existence of at least one intermediate layer, with its own characteristic scaling, between the traditional inner and outer layers. Other information is obtained, such as (i) the widths (in order of magnitude) of the four
Stress gradient balance layers and scale hierarchies in wallbounded turbulent flows
 J. Fluid Mech
"... Steady Couette and pressuredriven turbulent channel flows have large regions in which the gradients of the viscous and Reynolds stresses are approximately in balance (stress gradient balance regions). In the case of Couette flow, this region occupies the entire channel. Moreover, the relevant featu ..."
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Cited by 13 (10 self)
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Steady Couette and pressuredriven turbulent channel flows have large regions in which the gradients of the viscous and Reynolds stresses are approximately in balance (stress gradient balance regions). In the case of Couette flow, this region occupies the entire channel. Moreover, the relevant features of pressuredriven channel flow throughout the channel can be obtained from those of Couette flow by a simple transformation. It is shown that stress gradient balance regions are characterized by an intrinsic hierarchy of ‘scaling layers ’ (analogous to the inner and outer domains), filling out the stress gradient balance region except for locations near the wall. The spatial extent of each scaling layer is found asymptotically to be proportional to its distance from the wall. There is a rigorous connection between the scaling hierarchy and the mean velocity profile. This connection is through a certain function A(y+) defined in terms of the hierarchy, which remains O(1) for all y+. The mean velocity satisfies an exact logarithmic growth law in an interval of the hierarchy if and only if A is constant. Although A is generally not constant in any such interval, it is arguably almost constant under certain circumstances in some regions. These results are obtained completely independently of classical inner/outer/overlap scaling arguments, which require more restrictive assumptions. The possible physical implications of these theoretical results are discussed. 1.
Civil Engineering Faculty Publications Civil Engineering
, 2005
"... Modified log–wake law for zeropressuregradient turbulent boundary layers ..."
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Modified log–wake law for zeropressuregradient turbulent boundary layers
Loi logtrainée modifiée pour couche limite turbulente sans gradient de pression
"... Modified log–wake law for zeropressuregradient turbulent boundary layers ..."
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Modified log–wake law for zeropressuregradient turbulent boundary layers
Loi logtrainée modifiée pour couche limite turbulente sans gradient de pression
"... Modified log–wake law for zeropressuregradient turbulent boundary layers ..."
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Modified log–wake law for zeropressuregradient turbulent boundary layers