Drag Reduction Phenomenon in Water/Fine Solid Particle Suspensions.

Particle dispersion in sheared suspensions: Crucial role of solid-solid contacts

CFD Modeling of Binary-Fluidized Suspensions and Investigation of Role of Particle–Particle Drag on Mixing and Segregation

A model is presented for the prediction of the fluid dynamic behaviour of binary suspensions of solid particles fluidized by Newtonian fluids. The equations of motion for the fluid and solid phases are derived by extending the averaged two-fluid equations of change for identical spheres in Newtonian fluids developed by Anderson and Jackson and Jackson. A new closure relationship for the fluid–p...

Turbulent Drag Reduction by Spanwise Wall Oscillations

The objective of this paper is to examine the effectiveness of wall oscillation as a control scheme of drag reduction. Two flow configurations are considered: constant flow rate and constant mean pressure gradient. The Navier-Stokes equations are solved using Fourier-Chebyshev spectral methods and the oscillation in sinusoidal form is enforced on the walls through boundary conditions for the sp...

Drag Reduction by Surfactant Solutions in Gravity Driven Flow Systems

Efflux time measurements are carried out for gravity draining of a liquid from a large cylindrical tank (where the flow is essentially laminar) through single exit pipe in the absence and presence of Cetyl Pyridinium Chloride (CPC) surfactant solutions. The variables considered are initial height of liquid in the tank, dia. of tank, length of the exit pipe and concentration of surfactant. T...

Drag reduction by riblets.

The interaction of the overlying turbulent flow with riblets, and its impact on their drag reduction properties are analysed. In the so-called viscous regime of vanishing riblet spacing, the drag reduction is proportional to the riblet size, but for larger riblets the proportionality breaks down, and the drag reduction eventually becomes an increase. It is found that the groove cross section A(...