目的 针对现有定截面沟槽与凹坑结构整体减阻有限的问题,探明定截面与非定截面对流场调控以及减阻性能的差异,以剑鱼皮肤微结构为仿生对象,研究定截面到非定截面结构演化及其对应的减阻效应。方法 运用水洞实验和采用雷诺平均N-S方程结合RNG k-ε湍流模型数值模拟的对比方法,对仿生坑槽组合结构在不同来流速度下的减阻性能进行对比分析。结果 研究发现非定截面的等宽坑槽与收缩坑槽不具有减阻效果,而非定截面斜坡坑槽凭借“类滚珠效应”在低速下具有减阻效果,且在0.5 m/s时减阻峰值高达7.5%,高于定截面沟槽的减阻峰值5.5%。本研究提出了非定截面水下微结构减阻表面设计思路。结论 证实了非定截面在特定结构和尺寸下具有一定的减阻优势,“类滚珠效应”为表面减阻提供了新的方向,为水下潜航器的减阻优化设计提供一定的借鉴。
Abstract
The work aims to investigate the drag reduction characteristics of bionic pit and groove combined microstructure surfaces inspired by swordfish skin, focusing on the evolution from fixed-section to non-fixed-section structures and their corresponding effects on near-wall flow regulation. A series of bionic microstructures, including fixed-section U-shaped grooves (UG-SS), equal-width dents (DUD), contraction dents (DUS), and slope-shaped dents (DSD), were systematically designed to explore how geometrical variations affected drag reduction performance. The experimental methodology involved small-scale water tunnel tests, where test samples were precisely embedded into a baseplate to ensure smooth surface transitions and eliminate flow disturbances from gaps. Flow velocities ranged from 0.5 to 5 m/s, with each test condition repeated three times to obtain reliable average measurements. Complementary numerical simulations were conducted through Reynolds-averaged Navier-Stokes (RANS) equations coupled with the RNG k-ε turbulence model. The computational domain employed refined hexahedral and tetrahedral meshes near the microstructured wall, with grid independence confirmed at over one million elements. Periodic boundary conditions were applied in the streamwise and spanwise directions, with no-slip conditions on the top surface and the microstructured wall at the bottom, allowing detailed analysis of near-wall flow dynamics.
Experimental and numerical results showed that fixed-section UG-SS grooves exhibited a peak drag reduction of 5.5% at 1 m/s, characterized by low-speed region stabilization and suppression of turbulent fluctuations within the groove. Non-fixed-section slope-shaped dents (DSD) achieved a higher peak drag reduction of 7.5% at 0.5 m/s, demonstrating superior performance at low speeds. Equal-width dents (DUD) and contraction dents (DUS) consistently showed drag-increasing behavior across the tested velocity range, attributed to the generation of near-wall vortical structures that disrupted flow order and enhanced energy dissipation. The DSD structure induced a distinctive "ball-like effect" in which flow entering the slope-shaped pit formed recirculating vortices that isolated low-speed fluid near the wall from high-momentum mainstream flow, effectively moderating velocity gradients and delaying energy diffusion. Detailed velocity field analysis revealed that the DSD surface maintained coherent near-wall layers at low and medium velocities, while flow destabilization occurred at higher velocities due to vortex collapse and layer breakdown. In contrast, UG-SS grooves experienced gradual low-speed region expansion and velocity gradient weakening as flow speed increased, leading to transition from drag reduction to drag increase at higher velocities.
This work provides quantitative characterization of drag reduction performance for both fixed-section and non-fixed- section microstructures and identifies the key mechanisms governing their effectiveness. The slope-shaped DSD pits exhibit enhanced low-speed drag reduction due to vortex-mediated momentum isolation, while conventional fixed-section grooves offer moderate reduction through stable secondary vortices. These findings establish design principles for non-fixed-section underwater microstructured surfaces, offering a novel strategy for optimizing drag reduction in marine vehicles. The work demonstrates that careful geometric design of bionic microstructures can achieve targeted control of near-wall turbulence, providing a mechanistic basis for future applications in underwater vehicle efficiency enhancement.
关键词
仿生 /
坑槽组合 /
减阻率 /
流场特性 /
减阻特性
Key words
bionic /
pit and groove combination /
drag reduction rate /
flow field characteristics /
drag reduction characteristics
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 李政. 非光滑疏水表面的微气泡减阻技术研究[D]. 大连: 大连理工大学, 2013.
LI Z.The Study of Drag Reduction of Microbubbles on Nonsmooth Surface with Hydrophobic Property[D]. Dalian: Dalian University of Technology, 2013.
[2] CAFIERO G, IUSO G.Drag Reduction in a Turbulent Boundary Layer with Sinusoidal Riblets[J]. Experimental Thermal and Fluid Science, 2022, 139: 110723.
[3] ZHANG Y, CAI J S, LI W F.Direct Numerical Simulations of the Drag Degradation Mechanism in Channel Flow over Trapezoidal Riblets[J]. Aerospace Science and Technology, 2024, 144: 108821.
[4] 胡海豹, 宋保维, 潘光, 等. 鲨鱼沟槽表皮减阻机理的仿真研究[J]. 系统仿真学报, 2007, 19(21): 4901-4903.
HU H B, SONG B W, PAN G, et al.Simulation Studies on Drag Reduction Mechanism of Shark Riblets Surface[J]. Journal of System Simulation, 2007, 19(21): 4901-4903.
[5] WALSH M J.Turbulent Boundary Layer Drags Reduction Using Riblets[J]. AIAA Journal, 1982, 20(4): 485-486.
[6] ZHANG S Q, WU X Y, MA S, et al.Experimental and Numerical Simulation Study of Drag Reduction on AUV Grooved Surfaces[J]. Ocean Engineering, 2024, 314: 119610.
[7] 胡海豹, 宋保维, 潘光, 等. 回转体表面条纹沟槽减阻水洞实验研究[J]. 力学季刊, 2006, 27(2): 267-272.
HU H B, SONG B W, PAN G, et al.Water Tunnel Experimental Investigation on Drag Reduction in Gyroidal Objects with Riblets Surface[J]. Chinese Quarterly of Mechanics, 2006, 27(2): 267-272.
[8] 杨卓. 水下微结构功能表面设计及减阻特性[J]. 船舶工程, 2020, 42(1): : 141-147.
YANG Z.Underwater Micro-Structure Functional Surface Design and Drag Reduction Characteristics[J]. Ship Engineering, 2020, 42(1): : 141-147.
[9] SELVANOSE S M, MARIMUTHU S, AWAN A W, et al.NACA 2412 Drag Reduction Using V-Shaped Riblets[J]. Engineering, 2024, 5(2): 944-957.
[10] 徐继, 刘家强, 孙志宏. 三角形沟槽旋成体表面减阻性能的数值模拟[J]. 东华大学学报(自然科学版), 2011, 37(1): 105-108.
XU J, LIU J Q, SUN Z H.Numerical Simulation on the Drag Reduction of Body with Triangle Groove[J]. Journal of Donghua University (Natural Science Edition), 2011, 37(1): 105-108.
[11] 张营, 吕玉山. 叶序排布非光滑减阻表面的凹坑尺寸效应[J]. 新技术新工艺, 2014(5): 62-64.
ZHANG Y, LYU Y S.Effects of the Dimple Size of Non-Smooth Surface with Phyllotactic Pattern on Drag Reduction[J]. New Technology & New Process, 2014(5): 62-64.
[12] 徐成宇, 王永华, 焦远东, 等. 仿生鲨鱼皮表面的快速制备和减阻性能研究[J]. 表面技术, 2025, 54(5): 72-82.
XU C Y, WANG Y H, JIAO Y D, et al.Rapid Preparation and Drag Reduction Properties of Bionic Shark Skin Surfaces[J]. Surface Technology, 2025, 54(5): 72-82.
[13] 李茂林, 张浩, 玄克勇, 等. 三角形微沟槽壁面湍流减阻的数值研究[J]. 煤气与热力, 2023, 43(3): 18-24.
LI M L, ZHANG H, XUAN K Y, et al.Numerical Study on Turbulent Drag Reduction on Triangular Micro- Groove Wall[J]. Gas & Heat, 2023, 43(3): 18-24.
[14] 戎荣, 罗大海, 牛志罡. 圆柱表面沟槽减阻的大涡模拟研究[J]. 热能动力工程, 2023, 38(9): 113-122.
RONG R, LUO D H, NIU Z G.Large Eddy Simulation Study on the Effect of Drag Reduction Using Riblets Applied to the Surface of a Circular Cylinder[J]. Journal of Engineering for Thermal Energy and Power, 2023, 38(9): 113-122.
[15] GATTI D, QUADRIO M, CHIARINI A, et al.Turbulent Skin-Friction Drag Reduction via Spanwise Forcing at High Reynolds Number[J]. Journal of Fluid Mechanics, 2025, 1016: A58.
[16] LUO Z J, JIA X G, ZHU S N, et al.A Bio-Inspired Two-Stage Bionic Drag Reduction Method[J]. Review of Scientific Instruments, 2024, 95(3): 035118.
[17] CUI G Y, PAN C, WU D, et al.Effect of Drag Reducing Riblet Surface on Coherent Structure in Turbulent Boundary Layer[J]. Chinese Journal of Aeronautics, 2019, 32(11): 2433-2442.
[18] BACHER E, SMITH C.A Combined Visualization- Anemometry Study of the Turbulent Drag Reducing Mechanisms of Triangular Micro- Groove Surface Modifications[C]//Proceedings of the AIAA Shear Flow Control Conference. Boulder: American Institute of Aeronautics & Astronautics, 1985: 12-14.
[19] BECHERT D W, BRUSE M, HAGE W.Experiments with Three-Dimensional Riblets as an Idealized Model of Shark Skin[J]. Experiments in Fluids, 2000, 28(5): 403-412.
[20] 王鑫, 李山, 唐湛棋, 等. 沟槽对湍流边界层中展向涡影响的实验研究[J]. 实验流体力学, 2018, 32(1): 55-63.
WANG X, LI S, TANG Z Q, et al.An Experimental Study on Riblet-Induced Spanwise Vortices in Turbulent Boundary Layers[J]. Journal of Experiments in Fluid Mechanics, 2018, 32(1): 55-63.
[21] 黄明吉. 离心泵仿生微结构叶片减阻特性的仿真研究[J]. 表面技术, 2023, 52(2): : 196-205.
HUANG M J.Simulation Study on the Drag Reduction of Centrifugal Pump with Bionic Micro-Structured Blade[J]. Surface Technology, 2023, 52(2): : 196-205.
[22] VILKINIS P, ŠEREIKA J, PEDIŠIUS N, et al. Experimental Study of Flows over Triangular Riblets in Cavity-Like Geometry[J]. Experimental Thermal and Fluid Science, 2022, 134: 110621.
[23] EL-SAMNI O A, CHUN H H, YOON H S. Drag Reduction of Turbulent Flow over Thin Rectangular Riblets[J]. International Journal of Engineering Science, 2007, 45(2/3/4/5/6/7/8): 436-454.
[24] QIU H Y, CHAUHAN K, LEI C W.A Numerical Study of Drag Reduction Performance of Simplified Shell Surface Microstructures[J]. Ocean Engineering, 2020, 217: 107916.
基金
国家自然科学基金（52475264,52475358）
PDF(4445 KB)
渝公网安备 50010702501715号 渝ICP备15012534号-3
