An experimental investigation of the flow structure over a corrugated waveform in a transpired air collector

Investigation of fundamental flow mechanisms over a corrugated waveform using proper orthogonal decomposition and spectral analyses

“…These include spectral analysis in the wavenumber domain and proper orthogonal decomposition (POD) analysis. The turbulent velocity data from Greig et al [7,8] were used for these analyses.…”

“…This effect was more dominant at the lowest flow rate and diminishes as the flow rate increases. Greig et al [7,8] showed that at the lowest flow rate, the buoyancy effects dominated the flow in the channel and as the flow rate was increased, the buoyancy contribution diminished Comparing the heated and unheated flows at the highest flow rate, the almost identical energy distribution in the lower modes indicates that inertial effects dominate the lower modes up to mode 20. The energy contribution from the buoyancy-induced flow was mainly restricted to the higher modes with low relative energy differences.…”

“…The mean velocities and turbulent properties of the flow within a corrugated transpired air collector channel for an unheated collector have been examined by Greig et al [7]. For the unheated flow, the maximum mean velocity was shifted towards the plane construction wall and peaks of turbulent properties for an unheated flow were located at a height of one corrugation waveform.…”

“…The turbulence produced by the waveform was found to advect and dominate the whole channel, especially at high flow rates. Relatively large turbulent velocity magnitudes were observed at the lowest flow rate (Reynolds number corresponding to the laminar regime) within the trough sections, which were attributed to strong instabilities that were generated by the corrugation waveform [7]. Greig et al [8] investigated the influence of heat transfer from the corrugation wall on the mean and turbulent flow structure.…”

“…As the flow rate was increased, the magnitudes of mean velocity and turbulent properties became comparable to those observed for the unheated flow as forced convection became the dominant heat transfer mode. The results reported by Greig et al [7,8] suggest that there are mechanisms involved at different scales within the corrugated channel flow that are not fully understood, especially the instabilities induced by the corrugation waveform.…”