Assessment of unsteady cavitating flow around modified NACA4412 hydrofoil

Abstract

Cavitation is a complex two-phase flow phenomenon that includes unsteady characteristics. This work performs an unsteady 2D numerical analysis of cavitating flow on (i) cambered NACA4412 hydrofoil and (ii) the same hydrofoil geometry modified with dimple. The analysis is done with the objective of estimating the effect of the dimple on the hydrodynamic performance of the cavitating hydrofoil. The numerical simulations are performed using a flow solver by employing Realizable κ-ε turbulence model and Zwart-Gerber-Belamri (ZGB) cavitation model. The hydrodynamic performance is quantified in terms of coefficient of lift, coefficient of drag, lift to drag ratio, static pressure distribution, and cavity length at various cavitation numbers and angles of attack. From the assessment, it is observed that for 8⁰ angle of attack, the coefficient of drag on NACA4412 hydrofoil with the dimple is less as compared to NACA4412 without dimple. For higher angles of attack (α = 12⁰&16⁰) NACA4412 hydrofoil with the dimple has higher coefficient of lift compared to NACA4412 without dimple