Quantifying the Effect of Stable Stratification on Flow past Horizontal Cylinder

Stably stratified flows are encountered in different natural and industrial settings. The current research quantifies the effect stable stratification has on the fundamental phenomena of flow past a cylinder. Specifically, when the stratification is orthogonal to the direction of the flow, and the wake has a two-dimensional characteristics. These flows are simulated using open source spectral-element based high-order navier-stokes solver Nek5000. These simulations aim to capture and categorize the different flow structures induced by a cylinder in a stably-stratified flow. Simulations are first conducted for a wide range of Densimetric Froude numbers (Fr) and Reynolds numbers (Re), where Re is calculated using diameter as the length scale. Simulated Fr ranges between 0.01 to 1000 and simulated Re ranges between 10 to 180. The drag, lift, and Strouhal number are quantified. This allowed for the effect of increasing stratification on the vortex shedding to be quantified, including how the stratification changed the vortex shedding downstream of the cylinder. The structures formed are also classified using Dynamic Mode Decomposition (DMD).