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K.V. Prasad, H. Vaidya, K. Vajravelu, P.S. Datti and V. Umesh

Abstract

The present analysis is focused on the study of the magnetic effect on coupled heat and mass transfer by mixed convection boundary layer flow over a slender cylinder in the presence of a chemical reaction. The buoyancy effect due to thermal diffusion and species diffusion is investigated. Employing suitable similarity transformations, the governing equations are transformed into a system of coupled non-linear ordinary differential equations and are solved numerically via the implicit, iterative, second order finite difference method. The numerical results obtained are compared with the available results in the literature for some special cases and the results are found to be in excellent agreement. The velocity, temperature, and the concentration profiles are presented graphically and analyzed for several sets of the pertinent parameters. The pooled effect of the thermal and mass Grashof number is to enhance the velocity and is quite the opposite for temperature and the concentration fields.

Open access

K.V. Prasad, H. Vaidya and K. Vajravelu

Abstract

An unsteady boundary layer free convective flow and heat transfer of a viscous incompressible, microploar fluid over a vertical stretching sheet is investigated. The stretching velocity is assumed to vary linearly with the distance along the sheet. Two equal and opposite forces are impulsively applied along the x-axis so that the sheet is stretched, keeping the origin fixed in the micropolar fluid. The transformed highly non-linear boundary layer equations are solved numerically by an implicit finite difference scheme for the transient, state from the initial to the final steady-state. To validate the numerical method, comparisons are made with the available results in the literature for some special cases and the results are found to be in good agreement. The obtained numerical results are analyzed graphically for the velocity, the microrotation, and the temperature distribution; whereas the skin friction, the couple stress coefficient and the Nusselt number are tabulated for different values of the pertinent parameters. Results exhibit a drag reduction and an increase in the surface heat transfer rate in the micropolar fluid flow compared to the Newtonian fluid flow.

Open access

K. V. Prasad, Hanumesh Vaidya and K. Vajravelu

Abstract

An analysis is presented for mixed convection and heat transfer in a viscous electrically conducting fluid flow at an impermeable stretching vertical sheet with variable thickness. The nonlinear equations that describe the fluid flow, and heat transfer processes have been solved using the Keller-box method. A limited parametric study is undertaken to determine the sensitivity and changes in the flow and temperature fields with respect to variations in the buoyancy parameter, the temperature dependent viscosity and thermal conductivity parameters, the plate velocity power index, and the Prandtl number which are presented in graphical and tabulated formats. To validate the results, comparisons are made with the available results in the literature for some special cases and the results are found to be in good agreement. The effects of embedded parameters on the dimensionless velocity profiles and temperature are examined through graphs. The variation of Local Nusselt number is also analysed. One of the important findings of our study is that the velocity distribution at a point near the plate decreases as the wall thickness parameter increases and hence the thickness of the boundary layer becomes thinner when m < 1. Further, the effect of the magnetic field is to reduce the fluid velocity and to increase the temperature field.

Open access

P. Devaki, S. Sreenadh, K. Vajravelu, K. V. Prasad and Hanumesh Vaidya

Abstract

In this paper, the peristaltic wave propagation of a Non-Newtonian Casson liquid in a non-uniform (flexible)channel with wall properties and heat transfer is analyzed. Long wavelength and low Reynolds number approximations are considered. Analytical solution for velocity, stream function and temperature in terms of various physical parameters is obtained. The impact of yield stress, elasticity, slip and non-uniformity parameters on the peristaltic flow of Casson liquidare observed through graphs and discussed. The important outcome is that an increase in rigidity, stiffness and viscous damping force of the wall results in the enhancement of the size and number of bolus formed in the flow pattern.

Open access

K.V. Prasad, K. Vajravelu and I. Pop

Abstract

The boundary layer flow and heat transfer of a viscous fluid over a nonlinear permeable shrinking sheet in a thermally stratified environment is considered. The sheet is assumed to shrink in its own plane with an arbitrary power-law velocity proportional to the distance from the stagnation point. The governing differential equations are first transformed into ordinary differential equations by introducing a new similarity transformation. This is different from the transform commonly used in the literature in that it permits numerical solutions even for asymptotically large values of the power-law index, m. The coupled non-linear boundary value problem is solved numerically by an implicit finite difference scheme known as the Keller- Box method. Numerical computations are performed for a wide variety of power-law parameters (1 < m < 100,000) so as to capture the effects of the thermally stratified environment on the velocity and temperature fields. The numerical solutions are presented through a number of graphs and tables. Numerical results for the skin-friction coefficient and the Nusselt number are tabulated for various values of the pertinent parameters.

Open access

M. Ashok Kumar, A.M.K. Prasad, D.V. Ravishankar and G. Giridhar

Abstract

The effect of the fiber orientation in a laminate is investigated experimentally when subjected repeated quasistatic indentation. All the laminates with different fiber orientation are subjected to indentation with a stainless steel spherical indenter of diameter 8.0mm on a universal testing machine for a maximum indenter displacement of 4mm. The rate of indenter displacement was 0.5mm/minute. Different parameters like load bearing capacity, indentation diameter, area of surface damage, etc., were recorded after 4mm of indenter displacement. All the parameters were studied and compared to evaluate the laminate with high strength

Open access

K.V. Prasad, P. Mallikarjun and H. Vaidya

Abstract

The effect of thermal radiation and viscous dissipation on a combined free and forced convective flow in a vertical channel is investigated for a fully developed flow regime. Boussinesq and Roseseland approximations are considered in the modeling of the conduction radiation heat transfer with thermal boundary conditions (isothermal-thermal, isoflux-thermal, and isothermal-flux). The coupled nonlinear governing equations are also solved analytically using the Differential Transform Method (DTM) and regular perturbation method (PM). The results are analyzed graphically for various governing parameters such as the mixed convection parameter, radiation parameter, Brinkman number and perturbation parameter for equal and different wall temperatures. It is found that the viscous dissipation enhances the flow reversal in the case of a downward flow while it counters the flow in the case of an upward flow. A comparison of the Differential Transform Method (DTM) and regular perturbation method (PM) methods shows the versatility of the Differential Transform Method (DTM). The skin friction and the wall temperature gradient are presented for different values of the physical parameters and the salient features are analyzed.

Open access

M.S.N. Murty, G. Suresh Kumar, B.V. Appa Rao and K.A.S.N.V. Prasad

Abstract

In this paper, we provide a way to combine matrix Lyapunov systems with fuzzy sets to form a new system called fuzzy dynamical matrix Lyapunov system and obtain a suffcient condition for the controllability of this system.

Open access

M.V.S. Murali Krishna, N. Durga Prasada Rao, B. Anjeneya Prasad and P.V.K. Murthy

Abstract

It has been found that the vegetable oils are promising substitute, because of their properties are similar to those of diesel fuel and they are renewable and can be easily produced. However, drawbacks associated with crude vegetable oils are high viscosity, low volatility call for low heat rejection combustion chamber, with its significance characteristics of higher operating temperature, maximum heat release, and ability to handle lower calorific value (CV) fuel etc. Experiments were carried out to evaluate the performance of an engine consisting of different low heat rejection (LHR) combustion chambers such as ceramic coated cylinder head-LHR-1, air gap insulated piston with superni (an alloy of nickel) crown and air gap insulated liner with superni insert - LHR-2; and ceramic coated cylinder head, air gap insulated piston and air gap insulated liner - LHR-3 with normal temperature condition of crude rice bran oil (CRBO) with varied injector opening pressure. Performance parameters (brake thermal efficiency, brake specific energy consumption, exhaust gas temperature, coolant load, and volumetric efficiency) and exhaust emissions [smoke levels and oxides of nitrogen [NOx]] were determined at various values of brake mean effective pressure of the engine. Combustion characteristics [peak pressure, time of occurrence of peak pressure, maximum rate of pressure rise] were determined at full load operation of the engine.

Conventional engine (CE) showed compatible performance and LHR combustion chambers showed improved performance at recommended injection timing of 27°bTDC and recommend injector opening pressure of 190 bar with CRBO operation, when compared with CE with pure diesel operation. Peak brake thermal efficiencyincreased relatively by 7%, brake specific energy consumption at full load operation decreased relatively by 3.5%, smoke levels at full load decreased relatively by 11% and NOx levels increased relatively by 58% with LHR-3 combustion chamber with CRBO at an injector opening pressure of 190 bar when compared with pure diesel operation on CE

Open access

M. Sankar, M. Bhatt, G. R. Gowane, K. Narayanan, M. Kumar, A. K. Zahid, B. C. Saravanan, I. Allie, K. V. Subramani, A. K. Sharma and A. Prasad

Summary

Despite its high prevalence and pathogenicity, Stilesia globipunctata is a neglected cestode infection of ruminants in the tropics and sub-tropics. The present study reports the effect of sex, age, year and month on the prevalence of S. globipunctata in the goat. A total of 5208 eviscerated intestines of the goat carcasses were screened for a period of seven years, from January 2001 to December 2007. The overall prevalence of 36.6 % was significantly affected by the factors studied (P<0.05). Male goats were more susceptible to the S. globipunctata infection than that of female (P<0.05). Goat aged between 6 months and 1 year were found to be significantly more susceptible (P<0.05) which was followed by animals between 1 and 4 years of age and then more than 4 years of age. Morbidity was high (59 to 86 %) in animals of less than one year of age. The striking observation was that the prevalence peaked during monsoon and at nadir in May.