Ronan Boisard

Computational Fluid Dynamics as a Support to Counter-Rotating Open-Rotor Wind-Tunnel Test Analysis

The rising price of oil since the early 21st century produced a regain of interest in the counter-rotating open rotor, seen as an economic propulsive device for future transport aircraft. Although simple methods are used for design and optimization, the need for advanced methods to assess aerodynamic and acoustic performance of a counter-rotating open rotor within a complex configuration and to support wind-tunnel tests analysis is rising. In this paper, a methodology for complex counter-rotating open-rotor installations is set up to compute an actual test-rig geometry using high performance computing capabilities of ONERA computational-fluid-dynamics software elsA. Comparing the numerical results with the wind-tunnel test data enables to assess both the computational-fluid-dynamics code accuracy and the representativity of the wind-tunnel test, which relies on a somewhat intrusive test rig through a better understanding of the flowfield around the test rig.

In-plane airloads of a propeller with inflow angle: prediction vs. experiment

A comparison of the airloads on a propeller in incidence is done between experimental wind tunnel data, lifting-line results and unsteady Reynolds-Averaged Navier-Stokes (URANS) calculations. The experimental behaviour of the high-speed, scale-model, APIAN propeller in the transonic S1MA wind tunnel at various angles of attack at Mach 0.20 and Mach 0.70 is successfully predicted by ONERA’s Computational Fluid Dynamics (CFD) code elsA. An assessment is done on the ability of the two numerical methods, namely liftingline and URANS, to calculate propeller in-plane airloads. The importance of wake capture for accurate predictions is underlined and illustrated through comparisons on grid effects. Special emphasis is put on the airloads induced by the propeller on the spinner, which may amount up to 56% of the airloads on the propeller itself. Last, it is argued that neglecting these airloads biased the corrections done on the wind tunnel balance measurements.

Aeroacoustic Computation of a Contra Rotating Open Rotor Model with Test Rig Installation Effects

Aerodynamic and acoustic measurements of a scale model Contra Rotating Open Rotor (CROR) have been performed by TsAGI within the DREAM European Project. This paper presents the aerodynamic and aeroacoustic computations performed by ONERA to account for test rig installation effects on both aerodynamics and aeroacoustics. These numerical results are compared to experimental measurements for both validation and understanding of the installation impact of the test rig on noise emission.

Assessment of propeller 1P loads predictions

A comparison of the airloads on a propeller in incidence is done between experimental wind tunnel data, lifting-line results and unsteady Reynolds-averaged Navier-Stokes (URANS) calculations. The experimental behaviour of the high-speed, scale-model, APIAN propeller in the transonic S1MA wind tunnel at various angles of attack at Mach 0.20 and Mach 0.70 is successfully predicted by ONERA’s computational fluid dynamics (CFD) code elsA. An assessment is done on the ability of the two numerical methods, namely lifting-line and URANS, to calculate propeller in-plane airloads. The importance of wake capture for accurate predictions is underlined and illustrated through comparisons on grid effects. Special emphasis is put on the airloads induced by the propeller on the spinner, which may amount up to 56% of the airloads on the propeller itself. Last, it is argued that neglecting these airloads biased the corrections done on the wind tunnel balance measurements.

Influence of Blade Deformations on Open-Rotor Low-Speed and High-Speed Aerodynamics and Aeroacoustics

This paper investigates by means of computational fluid dynamics (CFD) and acoustic analogy the influence of blade deformations on open-rotor aerodynamics and aeroacoustics for three key operating points: cruise, takeoff, and approach conditions. For each operating point, simulation results obtained with unrunning blade shapes and running blade shapes are compared with wind tunnel test measurements. Experiments show that blade deformations affect mostly the front rotor, with twist deviations at tip varying within a range of ±2  deg and of opposite sign between cruise and takeoff conditions. Although blade deformations are low for the rear rotor, aerodynamic performance exhibits significant variations due to the modifications of the front rotor wash. Numerical results show that accounting for blade deformations increases or decreases the thrust or power depending on the operating point and leads to a much better prediction of the open-rotor aerodynamic performance. The same comments apply for the noise pre...