Antonio Jimenez-Garcia

CFD Simulations of the ERICA Tiltrotor using HMB2

Performance analysis of a 1:5 model-scale ERICA tiltrotor is presented, obtained using CFD. Three configurations, corresponding to minimum speed and high load for an aeroplane, corridor, and helicopter mode; are considered. For the aeroplane case, numerical simulations were based on the Unsteady Reynolds Averaged Navier-Stokes equations, where the rotor blades were fully resolved. The use of a uniform actuator disk was put forward as a means to quantify effect on the total loads. Comparisons with experimental data showed a good agreement and revealed the 4/rev. blade passage effect on the loads for the fully resolved approach. Results of the CFD with the uniform actuator disk also produced adequate estimates of the loads at the aerodynamic interaction zone. The effect of the model support in terms of Cp distribution was also investigated, where the straight mounted case was found to be less intrusive. Finally, visualisation of the flowfield using iso-surfaces of the Q-criterion confirmed the complex wake developed between the propeller and the tiltable wing. The corridor and helicopter mode configurations were also computed using a uniform actuator disk. For the corridor case, results showed an excellent agreement with the experiment data at cross sections on the fuselage, fixed wing, and tiltable wing of the ERICA tiltrotor. The helicopter CFD predictions were in fair agreement with the DNW-LLF experiment on the fuselage and fixed wing, while the peak of Cp distribution was under-predicted the region of aerodynamic interaction. The overall agreement with the experimental data demonstrated the capability of the present CFD method to accurately predict tiltrotor flows.

Numerical Simulations on the PSP Rotor Using HMB3

This work presents CFD analyses of the isolated Pressure Sensitive Paint (PSP) model rotor blade in hover and forward flight using the structured multi-block CFD solver of Glasgow University. In hover, two blade-tip Mach numbers (0.585 and 0.65) were simulated for a range of blade pitch angles using fully-turbulent flow and the k-ω SST model. Results at blade-tip Mach number of 0.585 showed a fair agreement with experimental Figure of Merit and surface pressure coefficients obtained in the Rotor Test Cell (RTC) at NASA Langley Research Center. Comparisons are presented at blade-tip Mach number of 0.65 in terms of integral blade loads, surface pressure coefficients and position of the tip-vortex cores with published numerical data. Finally, the flow around the PSP rotor in forward flight was also computed at medium thrust (CT =0.006) and results were compared with published experimental data.