Numerical Simulation of Rotor–Wing Transient Interaction for a Tiltrotor in the Transition Mode

Abstract

Tiltrotor aerodynamic interaction, especially in the transition mode, is a necessary consideration for tiltrotor aerodynamics, and structural design and optimization. Previous studies have paid much attention to the helicopter mode. However, due to the substantial complexity of the problem, only a small amount of work on the transition mode has been done so far. In this paper, the rotor–wing aerodynamic interaction of a scaled V-22 Osprey tiltrotor, both in the helicopter and transition modes, are studied by computational fluid dynamics (CFD) numerical simulation. The flow field is discretized via the chimera mesh technique and then solved with the Reynolds-averaged Navier–Stokes (RANS) equations. The rotational acceleration of the rotor is considered as a source term added on the right side of the momentum equation of the RANS equations. Both a quasi-steady and a fully transient method are employed to simulate the tilt motion of the rotor in the transition mode. Both qualitative and quantitative results are presented and discussed on the aerodynamic forces, flow physics, and mechanisms. The applicability of the extensively used quasi-steady method for rotor tilt simulation is revealed.

Wind Field Disturbance Analysis and Flight Control System Design for a Novel Tilt-Rotor UAV

“…Taking these challenges into consideration, many scholars have conducted numerous related studies in the simulation environment [9], [11], [13]- [19]. Regarding the nonlinear control problem of Tilt-rotor electrical vertical take-off and landing, [13] discussed a hovering state attitude control law based on nonlinear dynamic inversion, and successfully implemented and evaluated the proposed method in a proof of concept simulation.…”

“…During the vertical take-off and landing phase, the rotor nacelle system tilts to vertical position and works like a helicopter, the attitude and position of Tilt-rotor are controlled by direct force of rotor system. During these phases, the airspeed is so small that it cannot generate stable aerodynamic forces, and the aerodynamic interference which caused by wind field will reduce the stability of the aircraft [9], [20]- [22]. In [9], the rotor-wing aerodynamic interaction of a scaled V-22 Osprey Tilt-rotor in the helicopter mode was studied by computational fluid dynamics (CFD) numerical simulation.…”

“…During these phases, the airspeed is so small that it cannot generate stable aerodynamic forces, and the aerodynamic interference which caused by wind field will reduce the stability of the aircraft [9], [20]- [22]. In [9], the rotor-wing aerodynamic interaction of a scaled V-22 Osprey Tilt-rotor in the helicopter mode was studied by computational fluid dynamics (CFD) numerical simulation. However, the wind field was assumed to be zero and was not considered in the modeling in this paper.…”

An Innovative Control Allocation Framework for a Novel Tiltrotor Aircraft

“…During recent years, tiltrotor aircraft has gained remarkable attention on aviation industry [1][2][3][4] due to the broad flight envelope: from hover state, typical of rotorcraft, to high cruising-speed characteristic of fixed-wing aircraft. However, the unique structural characteristics, such as larger wing area and tiltable mechanism, make it a strong nonlinear and coupling system [5], [6]. Besides this, the number of control effectors and their dramatically change effectiveness with different flight states are great challenges for tiltrotor aircraft.…”

Effect of Needle Size and Volumetric Flow Rate on Root Canal Irrigation: A Numerical Investigation

“…Due to the difficulties of the experimental studies and their time consuming feature, efficient computational and numerical methods have been developed in recent decades [8][9][10][11]. Different computational methods are utilized in engineering systems to predict their performance and model their behavior [12][13][14][15][16].…”