Low-cost 3D color particle tracking velocimetry: application to thermal turbulence in water

Statistical performance of three-dimensional (3D) color particle tracking velocimetry (PTV) method based on the digital slit calibration proposed earlier by Noto et al. (Exp Fluids 62(6):1-13, 2021) was evaluated. The method utilizes only a color camera and a consumer-grade liquid crystal display projector (LCDP), and thus cost for implementation is significantly lower than that required for a tomographic system. Employment of an artificial neural network system enables to eliminate human decisions in constructing a color-to-depth conversion function. The method was examined in laminar and turbulent states of Rayleigh-Benard convection of water. The method reconstructed 3D flow fields and was able to capture the same statistics of velocity components in the in-plane and out-of-plane directions in the turbulent state. The results promise that the proposed low-cost, less expensive and quick, methodology has a potential to be an alternative to the state-of-the-art tomographic measurements.