实验流体力学2024，Vol.38Issue(2)：1-13,13.DOI:10.11729/syltlx20230136
水凝胶延迟水下回转体边界层自然转捩机理研究
Mechanism of natural transition delay by hydrogel metamaterial over a body of revolution
摘要
Abstract
Laminar-turbulence transition in a bow boundary layer is crucial for the performance of the bow sonar of an underwater vehicle.An investigation on the application of the hydrogel metamaterial on natural transition delay is conducted and the underlying mechanism is analyzed.The two-dimensional velocity fields around both rigid and hydrogel SUBOFF models are acquired by a long-distance PIV in a high-speed water tunnel,and drag coefficients are measured as well.Based on the velocity fields,the pressure fluctuations around the SUBOFF models are calculated through the multi-path integration algorithm.Combining the linear instability analysis and PIV measurement,the characteristics of natural transition of the boundary layer over the rigid SUBOFF model are analyzed.The flow-hydrogel coupling is figured out,according to the spectral analysis of local deformation of the hydrogel surface and the velocity above the hydrogel SUBOFF model in a low-speed water tunnel.The intermittency of the instantaneous boundary layer flows are denoted by continuous wavelet transform of the wall-normal velocity components.Eventually,compared with the flow intermittency of the rigid SUBOFF model,the mechanisms of natural transition delay by the hydrogel metamaterial are discussed,under the influence of the flow-hydrogel coupling.关键词
水下航行体/自然转捩/流动稳定性/转捩延迟/水凝胶超材料Key words
underwater vehicle/natural transition/flow instability/transition delay/hydrogel metamaterial分类
数理科学引用本文复制引用
刘建华,张彬,徐良浩,张占阳,潘翀,张永明,朱文博..水凝胶延迟水下回转体边界层自然转捩机理研究[J].实验流体力学,2024,38(2):1-13,13.基金项目
国家自然科学基金项目(91952301,91852101) （91952301,91852101）
