Stability of a Rotating Tank Source

The fundamental instabilities forming on source-sink model is reported. The rotation of fluid combined with fluid injection from a source ring placed an appreciable distance away from the axis and the fluid withdrawal generates a vortical structure similar to that seen in atmospheres Axisymmetric flow is computed on the meridional semi using a spectral-element discretisation, and stability to non axisymmetric perturbations is determined using a linear stability analysis. Direct numerical simulation (DNS) element-Fourier method verifies the stability predictions. solutions produce similar vortex structures physics. A global linear stability analysis predicts azimuthal wavenumber 13 arising from the flow which is higher than what was observed experimentally (wavenumbers Contour levels of the perturbation field indicate structures are located at the source, rather than the sink, where laboratory dye visualization has been focused. Three simulations suggest that these outer disturbances agitate lower wavenumber instabilities near the axis (pole)