Heat transfer effects on the oscillatory MHD flow in a porous channel with two immiscible fluids

The MHD oscillatory flow of two immiscible, viscous liquids in a porous channel with heat transfer is the subject of this investigation. The two liquid layers with different viscosities flow in both regions. The analytical expressions for velocity and temperature distribution have been derived by solving the governing flow equations using the regular perturbation method. The effects of various parameters on the velocity, temperature, and Nusselt number have been shown graphically, and numerical values of skin friction and flow rate are presented in tabular form and discussed. According to our analysis, the mass flux reduces as the magnetic field strength rises. While the temperature of the liquid enhances with an increase in the Eckert number and the Prandtl number, the temperature distribution rises with a decrease in the thermal conductivity ratio. To validate the results, the analytical solutions are compared with the fourth-order numerical Runge–Kutta method coupled with the shooting approach, and the results are found to be in excellent agreement

On the Performance of Latent Semantic Indexing-based Information Retrieval

Conventional vector based Information Retrieval (IR) models, Vector Space Model (VSM) and Generalized Vector Space Model (GVSM), represents documents and queries as vectors in a multidimensional space. This high dimensional data places great demands for computing resources. To overcome these problems, Latent Semantic Indexing (LSI): a variant of VSM, projects the documents into a lower dimensional space, computed via Singular Value Decomposition. It is stated in IR literature that LSI model is 30% more effective than classical VSM models. However statistical significance tests are required to evaluate the reliability of such comparisons. But to the best of our knowledge significance of performance of LSI model is not analyzed so far. Focus of this paper is to address this issue. We discuss the tradeoffs of VSM, GVSM and LSI and empirically evaluate the difference in performance on four testing document collections. Then we analyze the statistical significance of these performance differences

Dufour and Soret effects on pulsatile hydromagnetic flow of Casson fluid in a vertical non-Darcian porous space

This article aims to inspect the pulsating hydromagnetic slip flow of Casson fluid in a vertical porous channel with heat and mass transfer. The fluid is injected into the channel from the left wall and removed at the opposite wall with the same velocity. The impact of non-Darcy, Soret, and Dufour effects are taken under consideration. The governing partial differential equations (PDEs) are converted to ordinary differential equations (ODEs) using perturbation method and solved by utilizing 4th-order Runge–Kutta (R–K) technique together with shooting method. The impact of dissimilar parameters on flow, heat and mass transfer characteristics are displayed and discussed

Pulsating flow of Casson fluid in a porous channel with thermal radiation, chemical reaction and applied magnetic field

In the present analysis, the influence of thermal radiation, chemical reaction and thermal-diffusion on hydromagnetic pulsating flow of Casson fluid in a porous channel is investigated. The fluid is injected from the lower wall and sucked out from the upper wall with the same velocity. The governing flow equations are solved analytically by employing the perturbation technique. The influence of various emerging parameters on flow variables has been discussed. The obtained results show that the temperature distribution increases when there is an increase in heat source, whereas there is a decrease in temperature with an increase in radiation parameter. The concentration distribution decreases with an increase in chemical reaction parameter, while it increases for a given increase in Soret number. Further, the results reveal that, for both the Newtonian and non-Newtonian cases, Nusselt number distribution decreases at the upper wall with increasing Hartmann number and radiation parameter. The mass transfer rate decreases at the upper wall with increasing chemical reaction parameter and Soret number

MHD flow of non-Newtonian ferro nanofluid between two vertical porous walls with Cattaneo–Christov heat flux, entropy generation, and time-dependent pressure gradient

This article studies the magnetohydrodynamic flow of non-Newtonian ferro nanofluid subject to time-dependent pressure gradient between two vertical permeable walls with Cattaneo–Christov heat flux and entropy generation. In this study, blood is considered as non-Newtonian fluid (couple stress fluid). Nanoparticles’ shape factor, Joule heating, viscous dissipation, and radiative heat impacts are examined. This investigation is crucial in nanodrug delivery, pharmaceutical processes, microelectronics, biomedicines, and dynamics of physiological fluids. The flow governing partial differential equations are transformed into the system of ordinary differential equations by deploying the perturbation process and then handled with Runge–Kutta 4th-order procedure aided by the shooting approach. Hamilton–Crosser model is employed to analyze the thermal conductivity of different shapes of nanoparticles. The obtained results reveal that intensifying Eckert number leads to a higher temperature, while the reverse is true for increased thermal relaxation parameter. Heat transfer rate escalates for increasing thermal radiation. Entropy dwindles for intensifying thermal relaxation parameter

Entropy generation analysis for hydromagnetic two-layered pulsatile immiscible flow with Joule heating and first-order chemical reaction

The current research deals with the MHD pulsating flow of two immiscible liquid layers with joule heating and first-order chemical reaction. The channel is partitioned into two regions with different fluid widths. The governing flow equations are transformed using a perturbation approach into a system of ODEs. The R-K 4th-order approach is used with the shooting technique to solve the resulting ODEs. The effect of several emerging parameters on flow characteristics is depicted graphically and explained. The impact of liquid widths on velocity distribution, temperature and concentration are also presented for the cases: (i) when kerosene dominates the fluid flow, (ii) when water dominates the fluid flow, (iii) when both fluids occupy equal space in the channel. Moreover, the Nusselt and Sherwood numbers are calculated at the boundaries of the channel and presented through 3-D graphs. Further, shear stress for both channel walls and mass flux results are presented in tabular form. The outcome predicts that stress at the lower boundary is always greater than at the upper boundary. And, when the rate of heat transfer is measured over time, it has an oscillatory nature and is higher at the lower boundary than at the upper boundary

A note on the pulsatile flow of hydromagnetic Eyring–Powell nanofluid through a vertical porous channel

In this study, the pulsating flow of hydromagnetic nanofluid in a vertical porous channel has been investigated. Blood is considered as a base fluid that is non-Newtonian, and alumina $$(\mathrm{Al}_{2}\mathrm{O}_{3})$$, copper (Cu), silver (Ag) and gold (Au) are considered as nanoparticles. The effects of Joule’s heating and velocity slip at the walls are taken into consideration. Numerical results are obtained by solving the transformed differential equations using the Runge–Kutta fourth-order in addition to the shooting method. Influences of several flow controlling parameters including Grashof number, cross-flow Reynolds number, Hartmann number and frequency parameter on velocity and temperature profiles are examined graphically. The results elucidates that the velocity-slip plays an important role in increasing the heat transfer and velocity of the nanofluid. Further, the heat transfer rate by means of Nusselt number against different parameters is studied and the numerical results obtained are presented. It shows that heat transfer rate at the injection wall increased with increasing Grashof number, frequency parameter and radiation parameter

LATENT SEMANTIC INDEXING USING EIGENVALUE ANALYSIS FOR EFFICIENT INFORMATION RETRIEVAL

Text retrieval using Latent Semantic Indexing (LSI) with truncated Singular Value Decomposition (SVD) has been intensively studied in recent years. However, the expensive complexity involved in computing truncated SVD constitutes a major drawback of the LSI method. In this paper, we demonstrate how matrix rank approximation can influence the effectiveness of information retrieval systems. Besides, we present an implementation of the LSI method based on an eigenvalue analysis for rank approximation without computing truncated SVD, along with its computational details. Significant improvements in computational time while maintaining retrieval accuracy are observed over the tested document collections

Combined Effects of Chemical Reaction and Wall Slip on MHD Flow in a Vertical Wavy Porous Space with Traveling Thermal Waves

This paper investigates the magnetohydrodynamic (MHD) mixed convective heat and mass transfer flow in a vertical wavy porous space in the presence of a heat source with the combined effects of chemical reaction and wall slip condition. The dimensionless governing equations are perturbed into: mean (zeroth-order) part and a perturbed part, using amplitude as a small parameter. The perturbed quantities are obtained by perturbation series expansion for small wavelength in which terms of exponential order arise. The results obtained show that the velocity, temperature and concentration fields are appreciably influenced by the presence of chemical reaction, magnetic field, porous medium, heat source/sink parameter and wall slip condition. Further, the results of the skin friction and rate of heat and mass transfer at the wall are presented for various values of parameters entering into the problem and discussed with the help of graphs