Analysis of the remote microphone probe technique for the determination of turbulence quantities

[Display omitted] •Turbulence quantities determined from RMP measurements, such as convection velocity and correlation lengths, are influenced by the RMP setup, i.e., tube length and inner diameter.•The RMP phase must be considered to determine the turbulent structures’ convection velocity; otherwise, wrong estimations are obtained.•RMP tube inner diameter influences the coherence between a pair of RMPs. The coherence is reduced when the diameter decreases.•Turbulence quantities determined from the RMP and FMM measurements are different, mainly the coherence between a pair of microphones, directly impacting the estimation of the turbulence length scales.•The wall-pressure spectrum measured by the RMP is compared with the FMM, with a slight difference observed in the low-frequency range. Measuring the statistics of the wall-pressure fluctuations (WPFs) is essential for understanding and evaluating laminar/turbulent boundary layers and flow-induced noise. The remote microphone probe (RMP) technique is one of the most successful experimental approaches to measuring WPFs. Despite its extensive use in academic and industrial research, the scientific literature currently lacks an evaluation of the RMP influence on the determination of turbulence quantities, such as the WPF spectrum, the convection velocity, and the turbulence coherence length. To fulfill this necessity, this paper analyses the effects of the RMP on the determination of turbulence quantities, including comparisons between the results obtained using RMPs and flush-mounted microphones (FMMs). The RMPs and the FMMs measure the WPFs under a turbulent boundary layer developed on a zero-pressure-gradient flat wall. This study shows that the turbulence quantities determined from RMP measurements are influenced by the RMP setup, i.e., tube length and inner diameter. The tube length affects the phase between RMPs, which impacts the turbulent structure convection velocity estimation, which can be determined correctly by considering the calibrated phase. Furthermore, the tube inner diameter influences the coherence between a pair of RMPs, affecting the calculation of the turbulence correlation length. This research also shows that the turbulence quantities determined from the RMP and the FMM measurements differ, mainly in the coherence between pairs of microphones.