Optimal Feedback Force Locations in Measurement‐Integrated Simulation for Two‐Dimensional Flow Around a Circular Cylinder

ABSTRACT Measurement‐integrated simulation, one of the data assimilation methods, is a simulation technique that reproduces an actual flow field by adding feedback forces, including measurement data, to the external force term of the Navier–Stokes equations. The analysis in the previous studies using wind tunnels was limited to flows around a square cylinder. There is no principle for determining the optimal location of the feedback force, and the optimal location of feedback forces for other shapes is unknown. This study aimed to identify the optimal location for applying the feedback force in the flow around a circular cylinder and explore its relationship with the flow field. Using pressure on the cylinder surface obtained from a numerical experiment with disturbed inflow containing random fluctuations as measurement data, several measurement‐integrated simulations were conducted, each with a different feedback location. By comparing the results of the measurement‐integrated simulation with those of the numerical experiment, the optimal position was identified at 120° from the stagnation point that most accurately reproduced the flow behind the cylinder in the numerical experiment. Furthermore, this location was identified as the flow separation point, suggesting that applying a feedback force at the separation point is optimal for reproducing the flow behind the object.