...Karen A. Flack; Michael P. Schultz A review of predictive methods used to determine the frictional drag on a rough surface is presented. These methods utilize a wide range of roughness scales, including roughness height, pitch, density, and shape parameters. Most of these scales were developed...

... (of angles 2 deg and 3 deg) installed on the bottom wall of a plane channel. The experiments were conducted over a smooth surface and over transitionally rough and fully rough surfaces produced from sand grains and gravel of nominal mean diameters 1.55 mm and 4.22 mm, respectively. The dimensionless...

... turbulence channel flow friction pipe flow rough surfaces 07 07 2008 24 03 2009 13 05 2009 e-mail: karagoz@uludag.edu.tr e-mail: atakan@uludag.edu.tr 2009 American Society of Mechanical Engineers ...

... Reynolds number. The velocity distribution, just above the roughness level, turns out to be a universal relationship for all kinds of roughness (transitional, fully smooth, and fully rough surfaces), but depends implicitly on roughness scale. The open turbulent boundary layer equations, without any closure...

...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...

..., are employed with different rough surfaces. The nonuniform, irregular, 3-D roughness is characterized using the equivalent sand grain roughness size. Mach numbers along the airfoil range from 0.4 to 0.7. Chord Reynolds numbers based on inlet and exit flow conditions are 0.54 × 10 6 and 1.02 × 10 6...

... Engineering Division Sept. 12, 2002; revised manuscript received Apr. 22, 2003. Associate Editor: T. B. Gatski. 12 Sep 2002 22 Apr 2003 07 10 2003 channel flow rough surfaces microfluidics velocity A lab-on-a-chip device is a miniaturized laboratory on a chip consisting...

... 12 February 2003 27 08 2003 boundary layer turbulence rough surfaces surface topography friction flow simulation computational fluid dynamics interface phenomena Although numerical modeling of turbulent flows is continuously progressing, some questions remain open and need...

.... 3195 – 3204 . rough surfaces two-phase flow cavitation pipe flow pressure measurement flow visualisation The purpose of this work is to describe the two-phase flow structure of sheet cavitation. Cavitation is a sequence of vaporisation and condensation processes, related to the high...

... rough surfaces pumps pipe flow laminar to turbulent transitions turbulence In Eq. ( 3 ) C accounts indirectly for the influence of specific speed; C was determined empirically from tests with centrifugal compressors. Casey uses Re b 2 defined as above but determines...

... turbulence rough surfaces flow simulation drag Resistance in channel flow with wavy roughness The time discretization of Eq. ( 3 ) is written as (8) u i ¯ n + 1 − u i ¯ n = Δ t − ∂ u i ¯ u j ¯ ∂ x...

... Division May 23, 2000; revised manuscript received January 30, 2002. Associate Editor: D. R. Williams. 23 May 2000 30 January 2002 19 08 2002 boundary layer turbulence rough surfaces velocity measurement drag Turbulent boundary layers continue to be the subject of both...

... 2002 rough surfaces boundary layer turbulence drag friction polishing shear flow Many practical engineering applications involve turbulent flows over surfaces that have been smoothed by sanding. Examples range from sailing hulls to models for wind and water tunnels. While a great...

... for smooth-wall. Vertical and longitudinal turbulent flux of the shear stress on both smooth and rough surfaces is compared to those predicted by a turbulence model. The present results confirm that any turbulence model must take into account the effects of the surface roughness. Contributed...

... transitions laser Doppler anemometry boundary layers fluctuations rough surfaces Laminar-to-turbulent flow transition is a phenomenon which continues to be of interest to fluid mechanics scholars. In many technical applications, laminary boundary layers are induced, by roughnesses, to undergo...

...P. A. Durbin; G. Medic; J.-M. Seo; J. K. Eaton; S. Song A formulation is developed to apply the two-layer k − ε model to rough surfaces. The approach involves modifying the l ν formula and the boundary condition on k . A hydrodynamic roughness length is introduced and related to the geometrical...

... anemometer in shallow flows for three different types of rough surface, as well as a hydraulically smooth surface. The flow Reynolds number based on the boundary layer momentum thickness ranged from 1400 to 4000. The boundary layer thickness was comparable with the depth of flow and the turbulence intensity...

... 08 February 2000 boundary layer turbulence laser Doppler anemometry velocity measurement rough surfaces ships microorganisms 9 Turbulent normal stress u ′ 2 ¯ / U τ 2 for all the test surfaces @ x = 1.75   m (uncertainty in u...