Numerical instability investigation of inward radial Rayleigh–Bénard–Poiseuille flow

The spatial instability of inward radial Rayleigh–Bénard–Poiseuille flow was investigated using direct numerical simulations with random and controlled inflow forcing. were carried out a higher-order-accurate compact finite difference code in cylindrical coordinates. Inward flows can be found, for example, the collectors solar chimney power plants. conditions present chosen such that both steady unsteady three-dimensional waves are amplified. growth rates attenuated significantly downstream direction as result strong streamwise acceleration. For oblique waves, wave angles decrease phase speeds get larger increasing frequency. As travel downstream, increase. Overall, angle 90 ° most In general, because azimuthal extent, only certain wavenumbers possible. result, appear to merge direction. When is at an spiral formed, one family favored over other mode shapes left- right-traveling asymmetric respect radius. increases, this asymmetry aggravated wavenumber amplified disturbances diminished.