The effects of turbulence on the mean flow past square rods

Abstract

There are two main effects of turbulence on the mean flow past rods of square cross-section aligned with the approaching flow. Small-scale turbulence increases the growth rate of the shear layer, while large-scale turbulence enhances the roll-up of the shear layer. The consequences of these depend on the length of a square rod. The mean base pressure of a square rod varies considerably with turbulence intensity and scale as well as with its length.

On the Aeroelastic Behaviour of Rectangular Cylinders in Cross-Flow

“…The mean drag coefficient 0.82 is in good agreement with the results reported in Norberg (1993) which gives 0Á80. Also, Deniz & Staubli (1997) gives 0Á70 but for an experiment at a higher Reynolds number, whose effect is known to produce a lower drag force due to an earlier reattachment of the shear layers (Nakamura & Ohya 1983).…”

“…This effect was also studied in Novak & Tanaka (1974). Some of the other work is devoted to larger shape ratios (Li & Melbourne 1995;Matsumoto 2000) or to smaller ones (Nakamura & Ohya 1983, 1984Saathoff & Melbourne 1999). For large shape ratios, it was shown (Haan et al 1998) that the flow reattaches earlier when the intensity of turbulence is increased.…”

“…This grid was inspired from Nakamura & Ohya (1983) and Hinze (1975). The mesh size M=60 mm and is made up of 9 mm square rods.…”

Aerodynamics of a vibrating square prism in homogeneous turbulent flows

“…The corresponding reduced velocities, Ur = U/ND, are 5~13 in which the approaching wind velocity (IT) is always set at 6 m/sec and the corresponding Reynolds number, Re = pUD/įi, is then controlled at 3 x 10 4 . The approaching flow fields are generated by using square mesh grids, made of wooden rods and then mounted inside the tunnel prior to the model [6,11]. Five different homogeneous turbulent flows with different turbulence intensities (T.I.)…”

The Effects of Turbulence on Mean Flow Past Fixed and Oscillating Rectangular Prisms

“…Nakamura and Ohya [9,10] and, Nakamura and Ozono [ 11] indicated that the large turbulence scale is equivalent to the size of the entire near wake and increases the rolling-up of the shear layer. The small turbulence scale is equivalent to the thickness of the separated shear layer and increases its mixing growth rate.…”