Pressure Estimation from Stereo-PIV Data in a Two-Pass Rectangular Duct Before and at a Sharp 180° Bend

Abstract

Many thermal applications involve fluid flow across the sharp bend. The fluid flow across the sharp bend causes entire modification due to back pressure and flow separation, etc. Quantifying pressure across the sharp turn due to the modification of flow behaviour is always a complex challenge. One of the difficulties associated with the intrusive techniques of pressure measurements is to disturb the flow and the lack of pressure field estimation in the entire domain. This article presents a complete methodology for pressure estimation before and at the sharp bend using stereo-particle image velocimetry (PIV) data. The method relies on knowledge of the PIV velocity field, which is used to calculate the pressure field analytically and numerically. The outcomes of the study show that how the sharp bend in the fluid path results in a sharp pressure drop. Pressure at the entry of the bend is found to be ~5 Pa (absolute), and at the exit side, it drops to ~3 Pa for a turbulent in-flow condition (Reynolds number = 5500). The time-averaged streamlines are also superimposed over velocity magnitude and pressure data for a better understanding of flow and pressure simultaneously.