Strouhal-Reynolds number relationship for bluff-body flows numerically simulated by an artificial boundary method

Area of Science:

• Fluid Dynamics
• Computational Mechanics
• Numerical Analysis

Background:

• Investigating numerical resolution and blockage effects is crucial for accurate bluff body flow simulations.
• Existing embedding methods utilize artificial boundaries, necessitating parameter definition for accuracy.
• Bluff body flows, particularly around cylinders, are fundamental in aerodynamics and hydrodynamics.

Purpose of the Study:

• To investigate the impact of numerical resolution and blockage effects in an embedding method for bidimensional bluff body flows.
• To establish a method for determining the blur frontier ratio and blockage effect ratio.
• To validate the recovery of the universal Strouhal-Reynolds number relationship for circular cylinders.

Main Methods:

• An embedding method using artificial boundaries instead of exact surface conditions was employed.
• The blockage effect ratio was determined using the mean flow of a circular cylinder.
• The blur frontier ratio was obtained by comparing the embedding method with a direct numerical method, using flow past a square cylinder to minimize surface uncertainties.

Main Results:

• The study defines and quantifies the blur frontier ratio and blockage effect ratio.
• These ratios were found to effectively transform the Strouhal and Reynolds numbers for flow past a circular cylinder.
• The investigations confirmed the validity of the embedding method for bluff body flows.

Conclusions:

• The developed embedding method, with defined ratios, accurately simulates bidimensional bluff body flows.
• The method successfully recovers the established universal Strouhal-Reynolds number relationship for circular cylinders.
• This approach offers a robust alternative for analyzing flows around bluff bodies in computational fluid dynamics.