Yihao Qin

Insight into the interference effects of the nacelle position can be used to provide some guidance for achieving better aircraft performance in the preliminary design of modern civil aircraft. This paper investigates the through-flow nacelle position effects on aircraft aerodynamic characteristics and nacelle intake performances through numerical simulation. The Common Research Model with different nacelle-pylon installation positions is analyzed and all the five nacelle installation parameters, including spanwise position, penetration, gully depth, pitch angle, and toe angle, are systematically studied. Qualitative and quantitative comparisons between different configurations are conducted and the sensitivity of drag, lift distribution, total pressure recovery, and airflow distortion to nacelle position is obtained. The mechanism of interference effects is also explored. These derived insights can provide some guidance for determining the nacelle position and reduce the cost of subsequent wind tunnel test.

Landing a helicopter to the ship flight deck is most demanding even for the most experienced pilots and modeling and simulation of the ship-helicopter dynamic interface is a substantially challenging technical problem. In this paper, a coupling numerical method was developed to simulate the fully coupled ship-helicopter flow-field under complete wind-over-deck conditions. The steady actuator disk model based on the momentum source approach and the resolved blade method based on the moving overset mesh method were employed to model the rotor. Two different ship-helicopter combinations were studied. The helicopter flight mechanics model was established and then the influences of coupled airwake on the helicopter were analyzed. Finally, based on the derived rejection criterion of safe landing and the developed numerical method, the flight envelopes for these two ship-helicopter combinations were predicted. The steady actuator disk model was found to be effective in the study of helicopter operations in the shipboard environment. The calculated flight envelopes indicate that an appropriate wind direction angle is beneficial to increasing the allowable maximum wind speed and the operating boundary is affected by the rotation direction of the main rotor.

Despite the important role and highly frequent appearance of the helicopter in modern ship operations, the flight mission with take-off and landing of helicopters to ships, especially ships with small-sized decks, could be very challenging and potentially hazardous. Many researches on ship-helicopter dynamic interface (DI) have been conducted, and significant progress has been made. In this paper, a comprehensive and systematical review of the factors affecting the flying qualities of ship-borne helicopter and pilot workload during taking off and landing is derived from these efforts to date. The factors from two aspects, including the ship environment and the pilot-helicopter interface, are covered to address how these factors affect the helicopter handling qualities and pilot workload, primarily focusing on aerodynamic issues. The insight into these factors is not only of great significance for conducting take-off and landing tasks safely but also helpful to establish suitable fidelity criteria and guidelines for the modelling and simulation of the ship-helicopter DI environment.