Teaching Experiences

  • Feb. 03,2007 to date as a Professor at BUET Feb. 15, 1992 as a Lecturer at BUET

    Professor

    Department of Mathematics at BUET

Education & Training

  • PhD 2001

    Mathematics

    University of Bristol, UK

Honors, Awards and Grants

  • 1998
    Commonwealth Academic Staff Scholarship
    image

    Awarded for my PhD program.

    Also got Merit Scholarship fro Dhaka University.

Filter by type:

Sort by year:

Abstract

The asymptotic behaviour of ratios of differences of two convergents of a continued fraction is studied. In the first section the case of general continued fractions is considered, while in the second section limit k-periodic ones are treated. Necessary and sufficient conditions are obtained. The behaviour of ratios of the error is also studied and some acceleration methods are given

 A New Approach to Partial Differential approximan.

5. Rahman M M, Khan M A H

Abstract

A steady two-dimensional laminar magnetohydrodynamic (MHD) natural convection flow of viscous incompressible fluid with temperature dependent viscosity and thermal conductivity along a uniformly heated vertical wavy surface has been investigated. The governing boundary layer equations with associated boundary conditions are converted to non-dimensional form using a suitable transformation. The resulting nonlinear system of partial differential equations are mapped into the domain of a vertical flat plate and then solved numerically employing the implicit finite difference method, known as the Keller-box scheme. Depending on different flow conditions the abstract of the work are as follows:
Firstly, the effect of magnetohydrodynamic natural convection boundary layer flow along a vertical wavy surface with a temperature dependent viscosity (linear function and inversely proportional to linear function of temperature) has been analyzed. The results of the numerical solution are shown graphically in the form of skin friction coefficient, the rate of heat transfer, the velocity and temperature profiles, the streamlines and the isotherms over the whole boundary layer for different values of temperature dependent viscosity, magnetic parameter, the amplitude-to-length ratio of the wavy surface and Prandtl number. The skin friction coefficient and the rate of heat transfer are also displayed in tables showing the effects of viscosity, Prandtl number and the intensity of magnetic field.  
Secondly, the effect of temperature dependent thermal conductivity on magnetohydrodynamic natural convection flow of viscous incompressible fluid along a uniformly heated vertical wavy surface has been studied numerically. The effects of temperature dependent thermal conductivity, magnetic field, Prandtl number and the amplitude-to-length ratio of the wavy surface on the surface shear stress in terms of the skin friction coefficient Cfx, the rate of heat transfer in terms of Nusselt number Nux, the velocity and temperature profiles, the streamlines and the isotherms over the whole boundary layer are displayed graphically. Numerical results of the local skin friction coefficient and the rate of heat transfer for different values of thermal conductivity, Prandtl number and magnetic parameter have also been presented in tabular forms.
 vii
Thirdly, steady two-dimensional viscous incompressible fluid on magnetohydrodynamic free convection laminar flow with combined effects of temperature dependent viscosity and thermal conductivity of the fluid are taken to be proportional to a linear function of temperature along a uniformly heated vertical wavy surface have been considered. The numerical results of the surface shear stress in terms of skin friction coefficient Cfx and the rate of heat transfer in terms of local Nusselt number Nux, the stream lines and the isotherms have been presented graphically for a selection of parameters set consisting of temperature dependent viscosity, temperature dependent thermal conductivity, magnetic field, the amplitude-to-length ratio of the wavy surface and Prandtl number.  
Finally, the effect of Joule heating on MHD natural convection flow with viscosity and thermal conductivity variation owing to temperature along a uniformly heated vertical wavy surface has been studied. Here, the attention are focused on the surface shear stress in terms of the skin friction coefficient, the rate of heat transfer in terms of Nusselt number, the velocity, the temperature profiles, the streamlines and the isotherms for the effects of Joule heating, temperature dependent viscosity, temperature dependent thermal conductivity, the intensity of magnetic field, the amplitude-to-length ratio of the wavy surface and Prandtl number. In tabular form the numerical results of the local skin friction coefficient Cfx and the rate of heat transfer in terms of local Nusselt number Nux for different values of Joule heating parameter are also represented.  
Comparisons with previously reported investigations are performed and the results show excellent agreement

 A case study of methods of series summation: Kelvin-Helmholtz instability of finite amplitude

Khan M A H, Tourigny Y, Drazin P G

Abstract

High-order differential approximants

Khan M A H

Abstract

We introduce a new form of differential approximant for the summation of power series. The method is a special type of Padé–Hermite approximant. It consists of a high-order linear differential equation with polynomial coefficients that is satisfied approximately by the partial sum of the power series. This method is able to reproduce the polylogarithmic functions exactly. Numerical evidence suggests that this is currently one of the best methods of singularity analysis for many problems.

 Approximate method to flow in a rotating straight pipe

2. Khan M A H, Chowdhury

Abstract

A Numerical Study on Acoustic Streaming and Tissue Heating during Magnetic Resonance guided High Intensity Focused Ultrasound through Blood Vessel with an Obstacle

Paper Presentation

Description

Date: 03/04/2018

3rd Thermal and Fluids Engineering Conference (TFEC), (Paper Id : TFEC-2018-21810, ASTFE proceedings: PP-129-141)

At My Office

At My Work

Editor in Chief

GANIT-Journal of Bangladesh Mathematical Society

At My Lab

Professor Dr. Syed Ali Afzal

Computational Mathematics Laboratory