Measurement of pressure distribution from PIV experiments

Abstract

In this study, a non-staggered grid SIMPLER pressure solution algorithm, which is able to produce correct pressure distribution directly if correct velocities are given, is proposed to solve the pressure distribution for PIV experiments. The cell face pseudo velocity required in the pressure equation is approximated by a simple linear average of the adjacent nodal pseudo velocities so that the velocity and pressure are collocated without causing the checkerboard pressure distribution problem. In addition, the proposed pressure solution algorithm has the features that upwind effects of the convective terms are considered, boundary conditions are not required, and the pressure distribution obtained can be used to correct the velocity field so that the continuity equation is satisfied. These features make the present algorithm a superior method to calculate the pressure distribution for PIV experiments. The pressure field solved is realistic and accurate. The proposed pressure equation solver is first calibrated with a two-dimensional cavity flow. It is found that the results are almost identical to the exact solution of the test flow. The algorithm is then applied to analyze a uniform flow past two side-by-side circular cylinders in a soap film channel. With the velocity and pressure distributions successfully measured, the structures of the complex shedding flow patterns are clearly manifested.

Effects of turbulence on the mean pressure field in the separated-reattaching flow above a low-rise building

“…In addition to these techniques, algorithms in CFD have also been used to determine pressure from measured velocity data. For example, Jaw et al (2009) calculated the pressure distribution through the SIMPLER algorithm, in which continuity is satisfied and no boundary conditions are required. In contrast to these methods, in the current work we are applying the analytic interpolation approach proposed by Ettl et al (2008).…”

Optimization of planar PIV-based pressure estimates in laminar and turbulent wakes

“…The pressure gradient field may then be integrated, using for example one of the following methods proposed in previous studies: (1) Baur and Köngeter (1999) utilized a spatial marching scheme, (2) Liu and Katz (2006) developed an omni-directional line integration technique, (3) Dabiri et al (2014) proposed an eight-path line integration technique, (4) multiple authors solved the pressure Poisson equation using a standard 5-point discretization (Gurka et al 1999;Fujisawa et al 2005; de Kat and van Oudheusden 2012; Blinde et al 2016) or with an FFT integration simultaneously over the domain, (5) Tronchin et al (2015) solved local equations for the least squares approximation of the pressure field using an iterative method and (6) multiple authors (Regert et al 2001;Hosokawa et al 2003;Jaw et al 2009) have explored coupling the PIV velocity fields with common CFD algorithms to solve the pressure Poisson equation. Recent developments in tomographic PIV (Elsinga et al 2006) and three-dimensional particle tracking velocimetry (PTV) ) allow three-dimensional velocity field characterization inside a volume, further extending the capacity of pressure estimation (Violato et al 2011;Ghaemi et al 2012;Neeteson and Rival 2015;Laskari et al 2016;Schneiders et al 2016).…”

Reconstruction of the 3D pressure field and energy dissipation of a Taylor droplet from a $$\upmu$$PIV measurement

“…The second approach involves the direct integration of the momentum equation by means of finite differences. The main problem with the latter method is related to the accumulation of noise and integration error, which is successively incorporated into the derived pressure field (Baur 1999;Liu and Katz 2006;Jaw et al 2009;Tronchin et al 2015). Recently, Cai et al (2020) have proposed a variational formulation for the pressure-from-velocity problem in two dimensions.…”