Dharmendra Tripathi

Bio: Dharmendra Tripathi is an academic researcher from National Institute of Technology, Srinagar. The author has contributed to research in topics: Reynolds number & Nanofluid. The author has an hindex of 37, co-authored 188 publications receiving 4298 citations. Previous affiliations of Dharmendra Tripathi include Manipal University Jaipur & Birla Institute of Technology and Science.

A study on peristaltic flow of nanofluids: Application in drug delivery systems

Abstract: This paper studies the peristaltic flow of nanofluids through a two-dimensional channel. The analysis is conducted based on the long wavelength and low Reynolds number approximations. The walls of the channel surface propagate sinusoidally along the channel. The Buongiornio formulation for nanofluids is employed. Approximate analytical solutions for nanoparticle fraction field, temperature field, axial velocity, volume flow rate, pressure gradient and stream function are obtained. The impact of the pertinent physical parameters i.e. thermal Grashof number, basic-density Grashof number, Brownian motion parameter and thermophoresis parameter on nanoparticle fraction profile, temperature profile, velocity profile and trapping phenomenon are computed numerically. The results of this study demonstrate good correlation with the Newtonian results of Shapiro et al. (1969) [4], which is a special case ( Gr T = 0, Gr F = 0) of the generalized model developed in this article. Applications of the study include peristaltic micro-pumps and novel drug delivery systems in pharmacological engineering.

Peristaltic flow of viscoelastic fluid with fractional Maxwell model through a channel

Abstract: The paper presents the transportation of viscoelastic fluid with fractional Maxwell model by peristalsis through a channel under long wavelength and low Reynolds number approximations. The propagation of wall of channel is taken as sinusoidal wave propagation (contraction and relaxation). Homotopy perturbation method (HPM) and Adomian decomposition method (ADM) are used to obtain the analytical approximate solutions of the problem. The expressions of axial velocity, volume flow rate and pressure gradient are obtained. The effects of fractional parameters (@a), relaxation time (@l"1) and amplitude (@f) on the pressure difference and friction force across one wavelength are calculated numerically for different particular cases and depicted through graphs.

3D free convective MHD flow of nanofluid over permeable linear stretching sheet with thermal radiation

Abstract: This paper mainly focuses on the influence of transverse magnetic field as well as thermal radiation on three-dimensional free convective flow of nanofluid over a linear stretching sheet. One remarkable aspect of this study is that a new micro-convection model namely Patel model has been introduced in view of enhancement of thermal conductivity and hence more heat transfer capability of nanofluid. The non-linear partial differential equations have been converted into strong non-linear ordinary differential equations by employing suitable transformations and these transformed equations are solved by Runga-Kutta method of fourth order along with Shooting technique as well as Secant method for better approximation. From this study, it is found that the presence of magnetic field slows down the fluid motion while it enhances the fluid temperature leading to a reduction in heat transfer rate from the surface. It is also found that enhancing thermal radiation parameter causes a reduction in heat transfer rate.

Electroosmosis-modulated peristaltic transport in microfluidic channels

Abstract: We analyze the peristaltic motion of aqueous electrolytes altered by means of applied electric fields. Handling electrolytes in typical peristaltic channel material such as polyvinyl chloride and Teflon leads to the generation of a net surface charge on the channel walls, which attracts counter-ions and repels co-ions from the aqueous solution, thus leading to the formation of an electrical double layer—a region of net charges near the wall. We analyze the spatial distribution of pressure and wall shear stress for a continuous wave train and single pulse peristaltic wave in the presence of an electrical (electroosmotic) body force, which acts on the net charges in the electrical double layer. We then analyze the effect of the electroosmotic body force on the particle reflux as elucidated through the net displacement of neutrally buoyant particles in the flow as the peristaltic waves progress. The impact of combined electroosmosis and peristalsis on trapping of a fluid volume (e.g., bolus) inside the travelling wave is also discussed. The present analysis goes beyond the traditional analysis, which neglects the possibility of coupling the net pumping of fluids due to peristalsis and allows us to derive general expressions for the pressure drop and flow rate in order to set up a general framework for incorporating flow control and actuation by simultaneous peristalsis and application of electric fields to aqueous solutions. It is envisaged that the results presented here may act as a model for the design of lab-on-a-chip devices.

Mathematica simulation of peristaltic pumping with double-diffusive convection in nanofluids: a bio-nano-engineering model

Abstract: A theoretical study is presented to examine the peristaltic pumping with double-diffusive (thermal and concentration diffusive) convection in nanofluids through a deformable channel. The model is m...

Monthly Notices of the Royal Astronomical Society

Abstract: Monthly Notices is one of the three largest general primary astronomical research publications. It is an international journal, published by the Royal Astronomical Society. This article 1 describes its publication policy and practice.

Global Mittag-Leffler stability and synchronization of memristor-based fractional-order neural networks

Abstract: The present paper introduces memristor-based fractional-order neural networks. The conditions on the global Mittag-Leffler stability and synchronization are established by using Lyapunov method for these networks. The analysis in the paper employs results from the theory of fractional-order differential equations with discontinuous right-hand sides. The obtained results extend and improve some previous works on conventional memristor-based recurrent neural networks.

Simulation of nanofluid heat transfer in presence of magnetic field: A review

Abstract: Existence of magnetic field causes heat transfer to reduce in free convection but in several engineering uses for example: electronic application; enhancing heat transfer is a purpose. Thus, nanofluid should be selected as working fluid. Nanofluid is dispersion of very small metal particles in the base fluid. Two phase and single phase are two ways for estimating the behavior of nanofluid. At first model, nanofluid suppose as homogenous fluid without any slip mechanism. But in second method, slip velocities are included. Brownian motion and Thermophoresis impacts are taken into consideration in second approach. In this paper, previous publications about nanofluid hydrothermal treatment in existence of magnetic field are reviewed. Rely of variable and constant magnetic fields, Ferrohydrodynamic (FHD) and Magnetohydrodynamic (MHD) can take role in simulations. Numerical and analytical methods are considered by authors. Results proved that temperature gradient augments with augment of solid particle concentration and buoyancy forces, while it decreases with augment of magnetic field.