Abstract The present study seeks to conduct numerical investigations of the cavitating flow characteristics around a sinusoidal wavy leading edge (WLE) 3-D hydrofoil underlying a NACA 634–021 profile with an aspect ratio of 4.3. Cavitational and non-cavitational characteristics of hydrofoils are numerically examined at a chord-based Reynolds number of 7.2 × 105. The sinusoidal leading edge geometries include two WLE amplitudes of 5% and 25% and two WLE wavelengths of 25% and 50% of the mean chord length. We examined the cavitating flow around the hydrofoils in different cavitation numbers, namely σ = 0.8 and σ = 1.2. The flow over the protuberances of the WLE hydrofoil is considered at varying chord lengths and a constant angle of attack α = 6°, where significant spanwise variations in all flow properties, in contrast to the straight leading edge (SLE) hydrofoil, were observed. Large eddy simulation (LES) and Kunz mass transfer models are employed to simulate the dynamic and unsteady behavior of the cavitating flow. Besides, the compressive volume of fluid (VOF) method is used to track the cavity interface. Simulation is performed under the two-phase flow solver —interPhaseChangeFoam— of the OpenFOAM package. Compared to the SLE hydrofoil, we provided an exhaustive report of the time-averaged and instantaneous fluid dynamic characteristics of the cavitating flow around the sinusoidal leading edge hydrofoil, i.e., pressure, velocity, and vorticity fields, as well as lift and drag coefficients, and turbulent kinetic energy are reported. Furthermore, detailed analyses of the instantaneous cavity leading edge and flow separation treatment, vortical structure of the flow, vorticity stretching and dilatation, details of the spanwise flow, the formation of a low-pressure zone behind the WLE hydrofoil, streamwise velocity fluctuation, and evolution of the cavity dynamics through a complete cycle are reported. Results show that early development of the laminar separation bubble (LSBs) on the suction side of WLE hydrofoil prevents significant flow separation. Furthermore, the WLE cases exhibit a significantly reduced level of unsteady fluctuations in aerodynamic forces at the frequency of periodic vortex shedding.

中文翻译：

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具有波浪形前缘的 3-D 水翼非定常空化特性的 LES 研究

摘要 本研究旨在对纵横比为 4.3 的 NACA 634-021 剖面下方的正弦波浪前缘 (WLE) 3-D 水翼周围的空化流动特性进行数值研究。在基于弦的雷诺数 7.2 × 105 下对水翼的空化和非空化特性进行了数值检验。正弦前沿几何形状包括两个 5% 和 25% 的 WLE 振幅和两个 WLE 波长的 25% 和 50%平均弦长。我们检查了不同空化数下水翼周围的空化流，即 σ = 0.8 和 σ = 1.2。考虑在不同弦长和恒定攻角 α = 6° 下，WLE 水翼上的流动，其中所有流动特性的展向变化显着，与直前缘 (SLE) 水翼相反，观察到。采用大涡模拟 (LES) 和 Kunz 传质模型来模拟空化流的动态和非稳态行为。此外，流体压缩体积（VOF）方法用于跟踪腔界面。模拟是在 OpenFOAM 包的两相流求解器——interPhaseChangeFoam——下进行的。与 SLE 水翼相比，我们提供了正弦前缘水翼周围空化流的时间平均和瞬时流体动力学特性的详尽报告，即压力、速度和涡度场，以及升力和阻力系数，和湍动能被报道。此外，对瞬时腔前缘和流动分离处理的详细分析，报告了流动的涡结构、涡度拉伸和膨胀、展向流动的细节、WLE 水翼后面低压区的形成、流向速度波动以及整个循环中腔动力学的演变。结果表明，WLE 水翼的吸力侧层流分离气泡 (LSB) 的早期发展阻止了显着的流动分离。此外，WLE 情况下，在周期性涡流脱落频率下，空气动力的不稳定波动水平显着降低。结果表明，WLE 水翼的吸力侧层流分离气泡 (LSB) 的早期发展阻止了显着的流动分离。此外，WLE 情况下，在周期性涡流脱落频率下，空气动力的不稳定波动水平显着降低。结果表明，WLE 水翼的吸力侧层流分离气泡 (LSB) 的早期发展阻止了显着的流动分离。此外，WLE 情况下，在周期性涡流脱落频率下，空气动力的不稳定波动水平显着降低。