Triple decomposition and sparse representation for noisy pressure-sensitive paint data

TL;DR

This paper introduces a novel method for triple decomposition of noisy pressure-sensitive paint data, enabling accurate pressure distribution reconstruction with sparse sensors and minimal error, enhancing flow analysis capabilities.

Contribution

It proposes a simple phase-averaging method using multi-dimensional scaling, combined with sparse sensor optimization via a digital annealer, for improved pressure data analysis.

Findings

Small RMS error between measured and reconstructed pressure.

Effective pressure distribution reconstruction with few sensors.

Framework applicable for advanced flow analysis.

Abstract

Triple decomposition is a useful analytical method for extracting the mean value, organized coherent motion, and stochastic part from a fluctuating quantity. Although the pressure-sensitive paint (PSP) method is widely used to measure the pressure distribution on a surface, the PSP data measuring near atmospheric pressure contain significant noise. Here, we perform triple decomposition of noisy PSP data. To construct phase-averaged data representing an organized coherent motion, we propose a relatively simple method based on a multi-dimensional scaling plot of the cosine similarity between each PSP datum. Then, the stochastic part is extracted by selecting phase-averaged data with an appropriate phase angle based on the similarity between the measurement and phase-averaged data. As a data-driven approach, we also reconstruct the pressure distribution based on the triple decomposition and the pressure data at sparse optimal sensor positions determined from the proper orthogonal decomposition modes of the stochastic part. The optimal sensor positions are determined as a combinatorial optimization problem and are estimated using Fujitsu computing as a service digital annealer. Based on the results obtained, the root mean square error between the pressure measured by a pressure transducer and the reconstructed pressure obtained by the proposed method is small, even when the number of modes and sensor points is small. The application of PSP measurement is expected to expand further, and the framework for calculating triple decomposition and sparse representation based on the decomposition will be useful for flow analysis.