Rupjyoti Borah

@tingkhongcollege.edu.in

Assistant Professor, Department of Mathematics
Tingkhong College



              

https://researchid.co/rupjyoti

EDUCATION

M.Sc., M.Phil. & Pursuing PhD

RESEARCH, TEACHING, or OTHER INTERESTS

Applied Mathematics, Mathematical Physics, Numerical Analysis, Fluid Flow and Transfer Processes

FUTURE PROJECTS

Blood Flow through an annular region


Applications Invited
17

Scopus Publications

Scopus Publications

  • DUAL SOLUTIONS OF WATER-BASED MICROPOLAR NANOFLUID FLOW OVER A SHRINKING SHEET WITH THERMAL TRANSMISSION Stability Analysis
    Debasish Dey and Rupjyoti Borah
    National Library of Serbia
    Investigation of the nature of dual solutions of the water-based micropolar nanofluid-flow with thermal transmission due to a contracting surface has been done in the work. The flow is characterized by its shrinking velocity and imposed magnetic field. Also, this work is one of the contributions that illustrate the microrotation and microinertia descriptions of nanofluids. The effects of metallic nanoparticles Cu and CuO have been discussed throughout this study. A uniform magnetic field has been applied in the normal direction of the flow. A set of basic equations that supports the present problem are derived from the principle of conservation laws and have been modernized into a set of solvable forms by employing suitable similarity variables. The MATLAB built-in bvp4c solver scheme is engineered to solve this problem. In order to tackle boundary value problems that are highly non-linear, this numerical method largely relies on collocation and finite difference techniques. From this study, we have perceived that the speed of the motion of CuO-water nanofluid in both cases (the first and second solutions) is less than CuO-water nanofluid. The material parameter plays an important role by enhancing the heat transfer rate of the fluid at the surface of the sheet in both time-dependent and time-independent cases. From the stability analysis, the first solution has been found as the stable and physically attainable solution. Additionally, the material parameter aids in reducing the effects of couple stress and shear stress on the fluid in both situations near the surface.

  • Free Convection of a Radiating MHD Nanofluid Past a Solid Sphere with Energy Transfer in a Porous Medium
    Debasish Dey, Rupjyoti Borah, and O. D. Makinde
    Springer Science and Business Media LLC

  • DUAL SOLUTIONS OF HYBRID NANOFLUID FLOW OVER A CONE WITH THE INFLUENCE OF THERMAL RADIATION AND CHEMICAL REACTION AND ITS STABILITY ANALYSIS
    Debasish Dey, Rupjyoti Borah, and Ashim Jyoti Baruah
    V. N. Karazin Kharkiv National University
    The main intention of this study is to differentiate the stable and realisable solutions between the dual solutions of the water-based hybrid nanofluid flow driven by a solid cone along with energy transfer in the form of heat and mass by employing a new approach called stability analysis. The deviation of thermal radiation, chemical responses and heat absorption/generation are reserved into account. The leading equations which support the mathematical representation of this study are renovated by utilizing a set of similarity variables and solved by the MATLAB built-in bvp4c solver scheme. The outcomes of this study are presented both graphically and numerically. From this study, two kind of flow solutions have been achieved where one of them is related to the time-independent solutions and stable in nature. Also, the speed of the hybrid nanofluid can be controlled by applying magnetic field, but we should keep in mind that excessive amount of magnetic parameter may damage the system by burning.


  • EFFECTS OF HOMOGENEOUS AND HETEROGENEOUS REACTIONS ON THE WATER-BASED NANOFLUID STREAMING ABOVE AN EXTENDING SURFACE
    RUPJYOTI BORAH, Debasish Dey, and Madhurya Hazarika
    EdiUNS - Editorial de la Universidad Nacional del Sur
    The effect of homogeneous and heterogeneous reactions, as well as second-order velocity slip, on the magnetic influenced flow of nanofluid (Cu-water and MgO-water) passes above an extending surface has been examined. To alter the nature of leading equations of this problem, a new set of dimensionless variables have been employed. The resulting equations with the corresponding surface restrictions are solved using the Runge-Kutta-Fehlberg technique (RKF45) by developing a code in Maple-18. The outcomes of this investigation are presented in terms of pictorial mode with the effects of different novel flow parameters. Also, numerical values of physical quantities that are associated with this problem are set in terms of tabular mode. It is perceived that increasing the number of solid particles, the thermal and mass fractions of the nanofluid behave as an enhancing function, whereas the motion of the nanofluid is a decreasing function.

  • Flow of a Casson fluid with heat transfer over a shrinking sheet and its dual solutions




  • A Simulation of Nanofluid Flow with Variable Viscosity and Thermal Conductivity Over a Vertical Stretching Surface
    Debasish Dey, Rajesh Kumar Das, and Rupjyoti Borah
    Springer Nature Singapore


  • Stability analysis on dual solutions of MHD Casson fluid flow with thermal and chemical reaction over a permeable elongating sheet
    Debasish Dey, Rupjyoti Borah, and Ardhendu Sekhar Khound
    Wiley
    AbstractThe endeavor of this study is to explore the nature of dual solutions (steady and unsteady) for the Casson fluid flow with the simultaneous consequences of both thermal and mass transmissions. The flow passes above an absorbent elongating sheet in the existence of a constant magnetic field. The supported leading equations are remodeled into a set of solvable forms with the assist of suitable similarity variables and hence deciphered utilizing the “MATLAB routine bvp4c scheme.” Due to the sudden changes in the surface with time, the temperature and flow behavior over the sheet also change, and hence dual‐type flow solutions exist. Stability scrutiny is implemented to examine the less (more) stable and visually achievable solutions. From this study, we have achieved many interesting facts, among them, we can use magnetic and Casson fluid parameters to control the motion of the fluid and to enlarge of thermal transmission of the fluid. This flow model has many important applications in different physical fields, such as engineering sciences, medical sciences, and different industrial processes. One of the most important results, which has been achieved from this investigation, is that the Prandtl number enriches the heat transfer rate of the fluid at the surface during the time‐independent case under the suction environment. Also, the chemical reaction parameter helps to enhance the mass accumulation rate of the fluid in both cases.



  • Mathematical Modelling of Magnetized Nanofluid Flow Over an Elongating Cylinder with Erratic Thermal Conductivity
    Debasish Dey, Rupjyoti Borah, and Joydeep Borah
    Springer International Publishing

  • A STEADY CASSON FLUID FLOW PAST A STRETCHING POROUS SURFACE IN PRESENCE OF HEAT SOURCE AND CHEMICAL REACTION
    ARDHENDU SEKHAR KHOUND, DEBASISH DEY, and RUPJYOTI BORAH
    EdiUNS - Editorial de la Universidad Nacional del Sur
    In this problem a steady Casson fluid flow past an exponentially stretching porous surface is considered with Suction/blowing. Here a uniform magnetic field is applied in the transverse direction to the flow. The governing partial differential equations are reduced to a set of non-linear ordinary differential equations which are further solved numerically with the help of Matlab Build BVP4C technique. Results are discussed with the help of graphs and tables for various values of flow parameters. A special emphasize is given in the effect of Casson fluid parameter on fluid velocity, heat and mass transfer rate of the system.

  • Entropy generation analysis of magnetized micropolar fluid streaming above an exponentially extending plane
    Debasish Dey, Madhurya Hazarika, and Rupjyoti Borah
    EdiUNS - Editorial de la Universidad Nacional del Sur
    Numerical procedure of solving boundary value problems using MATLAB software has been applied to study the irreversibilies caused by magnetized micropolar fluid streaming above an extending surface. The factors responsible for irreversibilities are thermal and concentration distributions, Lorentz force etc. The entropy generation rates are shown pictorially through some figures and irreversibilities are shown in tabular form.
 Keywords-- MHD, Micropolar fluid, Heat transfer, Mass transfer, Exponentially stretching/shrinking sheet, Entropy generation.

  • DUAL SOLUTIONS OF BOUNDARY LAYER FLOW WITH HEAT AND MASS TRANSFERS OVER AN EXPONENTIALLY SHRINKING CYLINDER: STABILITY ANALYSIS
    Debasish Dey and Rupjyoti Borah
    EdiUNS - Editorial de la Universidad Nacional del Sur
    Boundary layer flow with heat and mass transfers over a stretching/shrinking cylinder has been investigated. The governing partial differential equations are converted into a set of ordinary differential equations using suitable similarity transformations and have been solved numerically using MATLAB built in bvp4c solver technique. The numerical results are graphically discussed in the form of velocity, temperature and concentration distributions for various values of flow parameters. Numerical results show that dual solutions are possible in specific range of the suction parameter. A stability analysis is executed to obtain which solution is linearly stable and physically realizable.