... phase turbulence, which includes the suppression and enhancement effects due to the presence of particles. For comparison, a two-layer model was also implemented since it has the capability to include surface roughness. The current study examines the predictions of the two-layer model for both clear gas...

... , “ Combined Effect of Surface Roughness and Heterogeneity of Wall Potential on Electroosmosis in Microfluidic/Nanofluidic Channels ,” ASME J. Fluids Eng. , 132 (4), p. 041103 . 10.1115/1.4001308 [12] Chen , C. K. , and Cho , C. C. , 2007 , “ Electrokinetically-Driven Flow Mixing...

...N. Rostamy; D. J. Bergstrom; D. Sumner; J. D. Bugg The effect of surface roughness on the mean velocity and skin friction characteristics of a plane turbulent wall jet was experimentally investigated using laser Doppler anemometry. The Reynolds number based on the slot height and exit velocity...

... in the overlap region is carried out by the Izakson-Millikan-Kolmogorov hypothesis. The velocity profiles and skin friction are shown to be governed by universal log laws as well as by universal power laws, explicitly independent of surface roughness, having the same constants as a fully smooth surface wall jet...

... found by Zhang and Ligrani ( 7 ). Figure 15 shows a schematic (not to scale) of the first two effects on the blade boundary layer thickness. Schematic of thickened wake due to roughness From the experimental results, the following conclusions can be made. 1 As the surface roughness...

... of the surface roughness profile and builds on previous work utilizing moments of the surface statistics. A relationship is given for the equivalent sandgrain roughness height as a function of the root-mean-square roughness height and the skewness of the roughness probability density function. Boundary layer...

... is not uniform in the bulk. The pressure gradient, which develops due to the nonuniformity of the form of EDLs and surface roughness, generates a nonuniform flow field in the bulk region above the obstacle. The mole fraction distributions (Fig. 7c ) show that for the strong solution the bulk fluid...

... in the water. 12 06 2007 03 05 2008 09 01 2009 bubbles chemical analysis hardness stainless steel surface roughness tempering ultrasonic applications vibrations wear cavitation erosion bubble dynamics thermal effect ultrasonic vibration cavitation It has been...

...Prashant R. Waghmare; Sushanta K. Mitra The present study is carried out to investigate the influence of surface roughness in combined electro-osmotic and pressure-driven flow in microchannel. Two-dimensional theoretical model is developed to predict the behavior of velocity profiles in rough...

... the effect of surface roughness on the impact dynamics of single cryogen droplets falling on skin models of various roughnesses ( 0.5 – 70 μ m ) . We first develop a theoretical model to predict the maximum spread diameter ( D m ) following droplet impingement based on a similarity approximation...

...Noor Afzal The present work deals with four new alternate transitional surface roughness scales for description of the turbulent boundary layer. The nondimensional roughness scale ϕ is associated with the transitional roughness wall inner variable ζ = Z + ∕ ϕ , the roughness friction Reynolds...

... , in terms of new scaling parameter, viz., the roughness Reynolds number Re ϕ = Re ∕ ϕ (where ϕ is a nondimensional roughness scale), is a universal relation for all kinds of surface roughness. This means that Prandtl’s smooth pipe friction factor relation would suffice provided that the traditional Reynolds...

..., Fluid Mechanics and Thermodynamics , Keffler, Shah and Ganic, eds., Elsevier Science Pub. Co., Inc. , New York, pp. 412 – 422 . Antonia , R. A. , and Krogstad , P. A. , 2001 , “ Turbulence Structure in Boundary Layer Over Different Types of Surface Roughness ,” Fluid Dyn. Res. 0169...

... roughness. Based on these first investigation results, water peening at 600 MPa may serve as a new method for introducing compressive residual stresses in engineering components. surface finishing jets drops microhardness plastic deformation surface roughness compressive strength internal stresses...

...A. S. Ziarani; A. A. Mohamad A molecular dynamics simulation of flow over two side-by-side cylinders with atomically rough surfaces is presented. The model is two-dimensional with 3 × 10 5 liquid argon atoms. The surface roughness is constructed by external protrusion of atoms on the surface...

... reduction lubrication surface roughness g gravity acceleration h height of the bubble r bubble’s curvature radius U velocity of the moving wall U 0 supply voltage R radius of the hole on circuit board Greek...

...Stephen T. McClain; S. Patrick Collins; B. Keith Hodge; Jeffrey P. Bons The discrete-element surface roughness model is used to provide insight into the importance of the mean elevation of surface roughness in predicting skin friction over rough surfaces. Comparison of experimental data...

...Qiang Zhang; Matt Goodro; Phillip M. Ligrani; Ricardo Trindade; Sri Sreekanth The effects of surface roughness on the aerodynamic performance of a turbine vane are investigated for three Mach number distributions, one of which results in transonic flow. Four turbine vanes, each with the same shape...

..., irrespective of the Reynolds number and surface condition. 12 08 2004 28 04 2005 friction boundary layer turbulence surface roughness Accurate determination of the skin friction on smooth and rough surfaces continues to be an important research topic in the near-wall turbulence...

...Mark F. Tachie; Donald J. Bergstrom; Ram Balachandar This paper investigates the effects of surface roughness on the transport and mixing properties in turbulent boundary layers created in an open channel. The measurements were obtained on a smooth and two different types of rough surfaces using...