Rotor wake and flow analysis using a coupled Eulerian–Lagrangian method

Abstract

A coupled Eulerian-Lagrangian methodology was developed in this paper in order to provide an efficient and accurate tool for rotor wake and flow prediction. A Eulerian-based Reynolds-averaged Navier-Stokes (RANS) solver was employed to simulate the grid-covered near-body zone, and a gridfree Lagrangian-based viscous wake method (VWM) was implemented to model the complicated rotor-wake dynamics in the off-body wake zone. A carefully designed coupling strategy was developed to pass the flow variables between two solvers. A sample case of a forward flying rotor was performed first in order to show the capabilities of the VWM for wake simulations. Next, the coupled method was applied to rotors in several representative flight conditions. Excellent agreement regarding wake geometry, chordwise pressure distribution and sectional normal force with available experimental data demonstrated the validity of the method. In addition, a comparison with the full computational fluid dynamics (CFD) method is presented to illustrate the efficiency and accuracy of the proposed coupled method. ARTICLE HISTORY

Methods of Preseting Boundary Conditions and Geometry of the Screw-Propeller in the Flow Vision

“…CFD-пакет Flow Vision успешно конкурирует с аналогичными пакетами, такими как STAR-CD, Ansys CFX, Fluent. В источниках [2,4,6,8,11] опубликованы результаты многочисленных экспериментов по исследованию гидродинамики судов, работы гребных винтов в свободной воде, проведённых в среде Flow Vision как разработчиками, так и пользователями программы. Но чаще всего результаты расчётов представлены посредством цветных рисунков, на которых визуализировано распределение давления и скорости потока при моделировании поставленных задач.…”

An investigation of coupling ship/rotor flowfield using steady and unsteady rotor methods

“…The Courant-Friedrichs-Lewy (CFL) number of 5 is set up in the solver. Validation of RADAS is demonstrated through a wide range of rotorcraft applications (Shi et al, 2016;Wang et al, 2013;Zhao et al, 2005); e.g. single rotor, dual-rotor interaction, and rotor/fuselage interaction.…”

“…Considering that the frequency of rotor rotation is larger than that of the shedding vortex of the ship airwake, to ensure the stability of the calculation, the time step is determined according to the period of rotor rotation. The analysis of time sensitivity in the rotor flowfield research has been investigated in our previous studies (Shi et al, 2016;Wang et al, 2013;Zhao et al, 2005). Thus, the rotor was resolved using 360 time steps per revolution, equal to 0.00047619 seconds per time-step.…”

“…In this paper, the numerical method of ship/helicopter coupling simulation has been developed with the help of previous studies (Shi, Xu, & Wei, 2016;Wang, Zhao, Xu, & Ye, 2013;Zhao, Xu, & Zhao, 2005), including the steady rotor model (SRM) based on the momentum source approach and the unsteady rotor model (URM) based on the moving overset mesh method. Qualitative analysis of complex interactions that arise from the ship/rotor wake in terms of vorticity and velocity for different wind angles and shipboard landing locations was performed for two typical ships: small-sized-deck destroyer and straight-through-deck ship.…”

Helicopter Blade-Vortex Interaction Airload and Noise Prediction Using Coupling CFD/VWM Method

“…To overcome the deficiencies of the existing coupled methods in BVI noise prediction, a high-resolution method coupling CFD and the viscous wake method (VWM), developed by Shi et al in [20,21], is employed for rotor wake simulation and impulsive airload calculation, and the generalized Farassat formulation based on the Ffowcs Williams-Hawkings (FW-H) Equation [22] is applied for noise prediction. The details of the coupled method are described in this paper.…”