In literature, we have two important branches of fluid mechanics, such as fluid dynamics and MHD. In fluid dynamics, the fluid motion is taken into the consideration with their physical properties like viscosity, porosity, density, thermal conductivity, permeability, surface tension, etc., whereas MHD flow is concerned with the magnetic field properties. Magnetohydrodynamics (MHD) is a fascinating branch of fluid mechanics. The magnetohydrodynamic is derived from magneto -meaning magnetic field, hydro-means water, and dynamics meaning movement. This prestigious branch of fluid mechanics was initiated by Hannes Alfven and for this, he obtained the Nobel Prize in physics in 1970. In the study of Magnetofluiddynamics, the Maxwell equations of the magnetic field are taken into consideration with Navier Stokes of fluid dynamics. The Navier Stokes equations were discussed by the famous mathematician Navier and Stokes for the incompressible and compressible fluid flow respectively, where compressibility of fluid is defined by the density property of the fluid. In the study of MHD flow, the governing nonlinear equations of flow are solved with the help of the perturbation method. The perturbation method is a useful method for the solution of nonlinear coupled differential equations. Although, this method has some limitations. In the present time, there are many numerical methods are obtained and discussed for the solution of high order nonlinear differential equations. The RK method with shooting techniques, HAM ( Homotopy analysis method), Laplace transformation, FEM (finite element method) are few important available methods.
The entropy generation (irreversibility distribution) due to magnetohydrodynamics (MHD) flow are also discussed in the field of fluid dynamics. The irreversibility distribution is possible due to a change in the temperature, friction of fluid particles, and the intensity of the magnetic field. The high intensity of the magnetic field enhances the total irreversibility distribution in the flow system, thus total entropy generation and their minimization can be controlled by suitably changing the strength of the magnetic field.
The field of magnetohydrodynamic has several important practical applications in the field of science and industries, such as petroleum and chemical industry, hydrology, thermal industry, etc. The MHD is also useful for cooling and heating various industrial devices and objects. It is also useful for cooling the nuclear reactor. The application of MHD fluid flow is also important in biomedical science, where blood flow and body temperature of patients can be controlled by appropriate use of the applied magnetic field. The other important applications of MHD flow are MHD power generator, MHD pump, MHD ship propulsion, etc.
Dr. Tarun Sharma
HOD, Department of Science
Biyani Group of Colleges