Stability analysis of MHD stagnation flow over a permeable heated rotating disk with heat generation/absorption.

MENDIL, F.; MAMACHE, S.; BOUDA, F. N.

THE STAGNATION POINT FLOW OF AN INCOMPRESSIBLE VISCOUS electrically conducting fluid impacting orthogonally on a heated rotating disk is studied with internal volumetric heat generation/absorption in the presence of a uniform magnetic field. A uniform suction or injection is applied through the surface of the disk. Appropriate similarity transformations are used to reduce the governing differential equations of the problem into a system of nonlinear ordinary differential equations and then solved numerically using the fourth-order Runge-Kutta method. In the second step, the work is oriented towards linear stability analysis by considering infinitesimally small disturbances within the boundary layer. Using normal mode decomposition in the Görtler-Hammerlin framework, the resulting eigenvalue problem is then solved numerically by means of the pseudo-spectral method using Laguerre's polynomials. As a result, the critical conditions for the onset of thermal instability are described and discussed in detail using multiple configurations. It is found that the presence of a magnetic field and suction/injection act to increase the stability of the basic flow. However, the rotation parameter and the internal heat generation/absorption contribute significantly to destabilizing the basic flow.

STAGNATION point; ROTATING disks; BOUNDARY layer (Aerodynamics); NONLINEAR differential equations; SIMILARITY transformations; STAGNATION flow

Archives of Mechanics, 2024, Vol 76, Issue 5, p471

0373-2029

Academic Journal

10.24423/aom.4535