This work has been numerically studied the fluid flow structure in the presence of magnetic field through a rotating rectangular straight duct under various flow conditions. Spectral method is applied as a main tool for the numerical calculation technique, where the Chebyshev polynomial, the Collocation method and the Newton-Raphson method are also used as secondary tools. The Magnetohydrodynamics incompressible viscous steady fluid flows in a straight duct of rectangular cross-section rotating at a constant angular velocity about the center of the duct of the cross-section is numerically investigated to examine the combined effects of Magnetic parameter(
M_g
), Rotational Parameter (
T_r
), Pressure driven parameter
(D_n
) and aspect ratio(γ)=b/a whereas a is the half width and b is the half height of the duct cross-section, Ω is the angular velocity, μ is the viscosity, ν is the kinematic viscosity. One of the interesting phenomena of the flow is the solution curve and the flow structure. The flow structures in case of small rotation of the duct axis and the pressure gradient with small Magnetic parameter as well as large Rotational Parameter and Large Magnetic Parameter have been considered while other parameters are remain constant. The calculations are carried out for 0.1⩽ M
_g
⩽ 32000, 5⩽ T
_r
⩽ 32000,
D_n =
500, 1000, 1500, 2000,9000,10000,11000,12000 and 12500 where the aspect ratio γ=1.0.
