roughness elements

roughness elements

[′rəf·nəs ‚el·ə·məns]
(oceanography)
Structures attached to laboratory models to simulate the roughness of the ocean floor.
References in periodicals archive ?
The structure should be designed so that a maximum allowable overflow rate of 2 l / s * m is achieved by a targeted arrangement of roughness elements in combination with eg a flood protection wall and / or a wave deflection wall.
Thompson, "On the excitation of Gortler vortices by distributed roughness elements," Theoretical and Computational Fluid Dynamics, vol.
The increased amount of roughness elements, which are mainly composed of buildings and road networks in urban areas, dramatically alters the surface roughness and urban boundary layer dynamics [2], which in turn results in more frequent air pollution and extreme weather.
In another experiment conducted by Verma and Prasad [4], roughness elements in the form of circular wires of different diameters were provided on the absorber plate at varying pitches.
Theoretically, [z.sub.0] has been found to be closely correlated with the geometry of surface elements including mean height, frontal area index (frontal area of roughness elements per unit ground area), plan area index (fraction of unit ground area covered by roughness elements), and the arrangement of roughness elements and is much heightened over urban surfaces because of the drag exerted by buildings and other infrastructures [18-22].
(1-3) have demonstrated experimentally that significant cycle time reductions can be achieved by adding pins (28% reduction) or roughness elements (18% reduction) to the exterior of a mold surface.
m = empirical factor accounting for the increased difference between maximum and mean shear stress on the erodible surface resulting from the flow around roughness elements (= 0.5)
Wall roughness elements will be designed using fractal patterns in order to isolate the multi-scale effects of the roughness geometry.
Additionally, ribs serve as artificial roughness elements in a fluid flowing channel to improve the convective heat transfer by creating turbulence in the flow.
* The use of some regular (normally rectangle) roughness elements [9] or irregular and randomly distributed roughness elements [10] in the computation domain.
A caliper rod (Figure 1) was used to read the linear distance, L2, resulting from roughness elements.
The performance of artificially roughened solar air heater has been tested experimentally over years for different shapes, sizes, and orientations of roughness elements to enhance the heat transfer coefficient with minimum pumping power.