Research on Submersible Oil Detection Based on Acoustic Vortex Technology

Abstract To address rapid and accurate identification of submerged oil in complex marine environments, this study proposes an underwater detection method based on acoustic orbital angular momentum (OAM). A uniform circular phased array synthesizes OAM beams with prescribed topological charge; numerical diffraction modeling and far-field Fourier reconstruction are used for echo-field recovery, topological-charge estimation, and OAM-spectrum characterization. Wavelet-domain thresholding is introduced to enhance weak-echo detectability. A COMSOL tank-oil-array model is built to evaluate the effects of array size, operating frequency, and topological charge. Results show that under m=1 and N=6, the OAM beam exhibits a stable zero-pressure core and annular energy distribution in oil-free conditions. With submerged oil present, impedance contrast induces phase mismatch and energy redistribution, leading to local splitting of the topological charge, vortex-core shift, and additional phase singularities. The reconstructed field and OAM spectrum provide discriminative features for submerged-oil identification, demonstrating the feasibility of OAM-based acoustic detection under multipath and noise.