Simultaneous Lateral Skewing in a Three-Dimensional Turbulent Boundary-Layer Flow

1970 ◽  
Vol 92 (1) ◽  
pp. 83-90 ◽  
Author(s):  
W. F. Klinksiek ◽  
F. J. Pierce
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Three Dimensional ◽  
Lateral Flow ◽  
Experimental Program ◽  
Boundary Layer Flows ◽  
Reversal Process ◽  
Incompressible Boundary ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

The results of an experimental program are reported on, wherein the lateral flow in a low-speed, three-dimensional, turbulent, incompressible boundary layer inside a recurving duct was made to reverse itself completely. In such a reversal process there occurs a region of flow where the boundary layer experiences lateral flow in two different lateral directions simultaneously. The physical arguments which support the existence of such flow regions with simultaneous lateral skewing are discussed and supported by the experimental results. Several of the more recent velocity profile models which are intended for use in describing skewed turbulent boundary-layer flows are reviewed as to their applicability to a flow with such simultaneous lateral skewing.

The Calculation of Three-Dimensional Turbulent Boundary Layers: Part II: Attachment-Line Flow on an Infinite Swept Wing

1967 ◽  
Vol 18 (2) ◽  
pp. 150-164 ◽  
Author(s):  
N. A. Cumpsty ◽  
M. R. Head
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Cross Flow ◽  
Swept Wing ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow ◽  
Momentum Integral ◽  
Attachment Line

SummaryAn earlier paper described a method of calculating the turbulent boundary layer flow over the rear of an infinite swept wing. It made use of an entrainment equation and momentum integral equations in streamwise and cross-flow directions, together with several auxiliary assumptions. Here the method is adapted to the calculation of the turbulent boundary layer flow along the attachment line of an infinite swept wing. In this case the cross-flow momentum integral equation reduces to the identity 0 = 0 and must be replaced by its differentiated form. Two alternative approaches are also adopted and give very similar results, in good agreement with the limited experimental data available. It is found that results can be expressed as functions of a single parameter C*, which is evidently the criterion of similarity for attachment-line flows.

Characterization of Thermals in a Heated Turbulent Boundary Layer

2019 ◽  
Author(s):  
Kadeem Dennis ◽  
Kamran Siddiqui
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Mixed Convection ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Mean Flow ◽  
Buoyant Force ◽  
Viscous Shear ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

Abstract The hydrodynamic boundary layer encountered in many practical engineering systems is turbulent in nature and known to play a significant role in governing the induced friction drag and species transport. In turbulent boundary layer flows, heat transfer is often involved which increases flow complexity due to the influence of buoyancy. When the buoyant force is sufficiently large in magnitude, thermals carrying heated fluid are known to detach and rise from the wall. Literature review shows that in mixed convection, thermals have been primarily identified through qualitative flow visualizations and there is a scarcity of their quantitative assessment. Furthermore, the evolution of thermals in the boundary layer with respect to flow inertia and viscous shear is not well-understood. Hence, there is a need for a better understanding of the dynamics of thermals in mixed convection turbulent boundary layer flow. The objective of this study is to experimentally investigate the three-dimensional nature of thermals rising from a turbulent boundary layer flow over a heated smooth horizontal flat plate. Experiments were performed in a closed loop low-disturbance wind tunnel with a test section featuring a 1 m long heated bottom wall. The multi-plane particle image velocimetry (PIV) technique was used to capture images in multiple planes with respect to the turbulent boundary layer mean flow direction for three-dimensional characterization. The measurements were conducted at Richardson numbers (Ri) of 0.3, 1.0, and 2.0. Flow visualization images are used to describe the nature of thermals and the dynamical processes involved during their interaction with bulk boundary layer flow. An image processing algorithm to detect thermals is then detailed and applied to experimental images. The performance of the new algorithm is then assessed in its ability to detect thermals.

scholarly journals Hot-Wire Measurements of Velocity and Temperature Fluctuations in a Heated Turbulent Boundary Layer

1984 ◽  
Author(s):  
M. F. Blair ◽  
J. C. Bennett
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layer Flow ◽  
Temperature Fluctuations ◽  
Present System ◽  
Maximum Frequency ◽  
Hot Wire ◽  
Boundary Layer Flows ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow

This paper describes the development of a multi-element hot-wire anemometry system designed to measure the fluctuating velocity and temperature in non-isothermal boundary layer flows. Special features of this system were that it utilized only standard constant-temperature anemometers and standard, commercially-available sensors. Although maximum frequency response for the present system was limited by the available signal digitization rates the probe/anemometry combination itself was shown to be capable of resolving signals to approximately 50 KHz. The performance of the system was evaluated by comparing velocity and temperature statistics measured in an equilibrium turbulent boundary layer flow with similar results from other investigations.

Effect of Reynolds number on drag reduction in turbulent boundary layer flow over liquid–gas interface

2020 ◽  
Vol 32 (12) ◽  
pp. 122111
Author(s):  
Hongyuan Li ◽  
SongSong Ji ◽  
Xiangkui Tan ◽  
Zexiang Li ◽  
Yaolei Xiang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Turbulent Boundary Layer ◽  
Drag Reduction ◽  
Boundary Layer Flow ◽  
Turbulent Boundary Layer Flow ◽  
Layer Flow
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