S. Sreenadh

Peristaltic pumping of a Herschel-Bulkley fluid in a channel

Peristaltic transport of Herschel-Bulkley fluid in a channel is investigated. The effects of yield stress and wave amplitude on the pumping characteristics are obtained and discussed. It is observed that for Herschel-Bulkley fluid, the peristaltic wave passing over the channel wall pumps more fluid against pressure rise compared to a power-law fluid. Furthermore, the results for trapping phenomena are obtained and discussed for Newtonian, Bingham, power-law and Herschel-Bulkley fluids.

Influence of Lateral Walls on Peristaltic Flow in a Rectangular Duct

The flow of a viscous fluid due to symmetric peristaltic waves propagating on the horizontal sidewalls of a rectangular duct is studied under the assumptions of long wavelength and low Reynolds number. The effect of aspect ratio

Mathematical model for a Herschel-Bulkley fluid flow in an elastic tube

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Pulsatile flow between permeable beds

, ratio of height to width, on the pumping characteristics is discussed in detail. The results are compared to with those corresponding to Poiseuille flow.

Peristaltic transport of a Herschel-Bulkley fluid in contact with a newtonian fluid

The constitution of blood demands a yield stress fluid model, and among the available yield stress fluid models for blood flow, the Herschel-Bulkley model is preferred (because Bingham, Power-law and Newtonian models are its special cases). The Herschel-Bulkley fluid model has two parameters, namely the yield stress and the power law index. The expressions for velocity, plug flow velocity, wall shear stress, and the flux flow rate are derived. The flux is determined as a function of inlet, outlet and external pressures, yield stress, and the elastic property of the tube. Further when the power-law index n = 1 and the yield stress τ0 → 0, our results agree well with those of Rubinow and Keller [J. Theor. Biol. 35, 299 (1972)]. Furthermore, it is observed that, the yield stress and the elastic parameters (t1 and t2) have strong effects on the flux of the non-Newtonian fluid flow in the elastic tube. The results obtained for the flow characteristics reveal many interesting behaviors that warrant further study on the non-Newtonian fluid flow phenomena, especially the shear-thinning phenomena. Shear thinning reduces the wall shear stress.

Combined free and forced convection in an inclined channel with permeable boundaries

Abstract Pulsatile flow of a viscous fluid between two permeable beds is analyzed. The flow between and through the permeable beds are governed by the Navier–Stokes equations and Darcys law, respectively. The velocity field and the volume flux are obtained for several cases and discussed. Further, when the permeability parameter k→0, the results agree with those of Wang (J. Appl. Mech. 38 (1971) 553).

Peristaltic Flow of a Bingham Fluid in Contact with a Jeffrey Fluid

Peristaltic transport of Herschel-Bulkley fluid in contact with a Newtonian fluid in a channel is investigated for its various applications to flows with physiological fluids (blood, chyme, intrauterine fluid, etc.). The primary application is when blood flows through small vessels; blood has a peripheral layer of plasma and a core region of suspension of all the erythrocytes. That is, in the modeling of blood flow, one needs to consider the core region consisting of a yield stress fluid and the peripheral region consisting of a Newtonian fluid. Peristaltic pumping of a yield stress fluid in contact with a Newtonian fluid has not previously been studied in detail. Our goal is to initiate such a study. The Herschel-Bulkley fluid model considered here reduces to the power law model in the absence of yield stress. The stream function, the velocity field, and the equation of the interface are obtained and discussed. When the yield stress TO → 0 and when the index n = 1, our results agree with those of Brasseur et al. (J. Fluid Mech. 174 (1987), 495) for peristaltic transport of the Newtonian fluid. It is observed that for a given flux Q the pressure rise Ap increases with an increase in the amplitude ratio Φ. Furthermore, the results obtained for the flow characteristics reveal many interesting behaviors that warrant further study of the peristaltic transport models with two immiscible physiological fluids.

MHD peristaltic flow of a hyperbolic tangent fluid in a non-uniform channel with heat and mass transfer

Abstract Combined convection in an inclined channel bounded by porous walls is studied. Expressions for the velocity distribution, mass flow rate, and its fractional increases are obtained. When the upper permeable bed is at rest (U = 0), the results are in agreement with that of Rudraiah and Wilfred (Nat. Acad. Sci. Lett. 3 (1980) , 49). Further, when the permeability parameter k → 0, the results agree with that of Ruth (“Department Report 129,” Univ. of Calgary, 1978) .

Effects of Slip and Heat Transfer on the Peristaltic Pumping of a Williamson Fluid in an Inclined Channel

The article concerns the peristaltic transport of two-layered fluid, consisting of a Bingham fluid in the core region and a Jeffrey fluid in the peripheral region through a channel. The flow is analyzed in the wave of reference under the assumptions of long wavelength and low Reynolds number. The analytical expressions for stream function, pressure rise, and the frictional force per wavelength in both the regions are obtained. The effect of physical parameters namely yield stress, Jeffrey parameter associated with the flow are presented graphically. This model helps to understand the behavior of two immiscible physiological fluids in living structures and in modeling the biomechanical instruments.

Peristaltic transport of a Herschel–Bulkley fluid in an inclined tube

The influence of elastic wall properties on the peristaltic transport of a conducting hyperbolic tangent fluid in a non-uniform channel is investigated with heat and mass transfer. The flow is examined in a fixed frame of reference under the assumptions of long wavelength and low Reynolds number. The velocity slip, temperature and concentration jump boundary conditions are considered at the walls. The perturbation method of solution for stream function, velocity, temperature, concentration and the coefficient of heat transfer are obtained in terms of small Weissenberg number. The influence of several pertinent parameters on the flow are discussed by plotting graphs. The trapping phenomenon is also analysed. It is noticed that the size of the trapping bolus increases with increasing the power law index of hyperbolic tangent fluid.