Fluid dynamic characteristics of the flow over an array of large roughness elements

Flow visualization and measurements of velocity and turbulence intensity using laser Doppler velocimetry are used to investigate separation and reattachment processes in the flow over an array of protruding elements mounted on the bottom wall of a rectangular water channel. The concept of an array shear layer is introduced to demarcate the region of influence over which the resistance of the array retards the flow. Flow separation at the leading edge of the elements is documented. The confined or interacting nature of the flow in the cavities between elements is established as a function of element spacing. The reattachment length downstream of the element varies from 4 to 1.5 element heights, decreasing both with an increase in Reynolds number and a decrease in channel height.

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A Computational Fluid Dynamic Study of a Momentum and Energy Method on Rough Surfaces

Volume 3: Computational Fluid Dynamics; Micro and Nano Fluid Dynamics ◽

10.1115/fedsm2020-20345 ◽

2020 ◽

Author(s):

Jose Urcia ◽

Michael Kinzel

Keyword(s):

Heat Transfer ◽

Fluid Dynamic ◽

Roughness Element ◽

Flow Rates ◽

Pressure Drops ◽

The Core ◽

Roughness Elements ◽

Momentum Correlation ◽

The Matrix ◽

Computational Fluid Dynamics Cfd

Abstract The Discrete Element Roughness Method (DERM) has been used to improve convective heat transfer predictions on surface roughness. This work aims to validate the core momentum-correlation of DERM through evaluating Computational fluid dynamics (CFD)-based solution of the flow around individual roughness elements with the goal of improving the correlations. More specifically, the matrix of scenarios evaluated using includes three different roughness elements at three different pressure drops (or flow rates). Results from these studies are to be used to validate and improve correlations used to approximate roughness in DERM. For further comparison, a fourth roughness element analyzed in previous work will also be compared. For each element, a steady and unsteady case are conducted and analyzed. The momentum loss results obtained from the CFD are then compared to the DERM-based predictions from the same roughness elements in search of any discrepancies. It is observed the momentum-correlation deviates from the CFD prediction with increasing element height.

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Effect of initial tangential intensity on the fluid dynamic characteristics in tangential burner

MATEC Web of Conferences ◽

10.1051/matecconf/201710103001 ◽

2017 ◽

Vol 101 ◽

pp. 03001

Author(s):

Pasymi ◽

Yogi Wibisono Budhi ◽

Yazid Bindar

Keyword(s):

Dynamic Characteristics ◽

Fluid Dynamic

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Numerical Study of XCP Probe's Fluid Dynamic Characteristics

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.130-134.1645 ◽

2011 ◽

Vol 130-134 ◽

pp. 1645-1649

Author(s):

Ning Liu ◽

Rui Zhang ◽

Wen Yi Chen ◽

Man Man Zhang

Keyword(s):

Numerical Analysis ◽

Drag Coefficient ◽

Dynamic Characteristics ◽

Numerical Study ◽

Fluid Dynamic ◽

Steady Motion ◽

Experimental Results ◽

Analysis Method ◽

Test Parameters ◽

Volume Method

Applied the finite volume method combining two-equations turbulence model,the influence of fluid dynamic characteristics on XCP probe under different factors be studied The fluid dynamic characteristics were researched under different influencing factors, such as falling speed, rotating rate,seawater density,etc. The drag coefficient under the different falling speeds and the limited velocity of submarine steady motion were obtained. Compared with the experimental results, the simulated results agree well with experimental results, the experiments have show the validity and feasibility of the numerical analysis method. These results will provide theory reference for selecting the reasonable rotating rate, analyzing stability and the movement rule of probe in the water, choosing suitable test parameters for XCP probe of different seawaters.

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