Estimation of three-dimensional aerodynamic damping using CFD

Abstract

Aeroelastic phenomena of stall flutter are the result of the negative aerodynamic damping associated with separated flow. From this basis, an investigation has been conducted to estimate the aerodynamic damping from a time-marching aeroelastic computation. An initial investigation is conducted on the NACA 0012 aerofoil section, before transition to 3D propellers and full aeroelastic calculations. Estimates of aerodynamic damping are presented, with a comparison made between URANS and SAS. Use of a suitable turbulence closure to allow for shedding of flow structures during stall is seen as critical in predicting negative damping estimations. From this investigation, it has been found that the SAS method is able to capture this for both the aerofoil and 3D test cases.

A computational fluid dynamic acoustic investigation of a tiltwing eVTOL concept aircraft

“…Good agreement in terms of aerodynamics, acoustics and aeroelasticity were seen by all [27,28,29,30].…”

An Aeroacoustic Investigation of a Tiltwing eVTOL Concept Aircraft

“…Previous investigations using HMB3 have provided propeller flow validation in both installed and isolated conditions, by comparison with the experimental results of the Joint Open Rotor Propeller (JORP) blade [9], the Improving the Propulsion Aerodynamic and aCoustics of Turboprop Aircraft (IMPACTA) wind tunnel tests [10,11] and the model aircraft propeller inflow investigation at the University of Glasgow. Good agreement in terms of aerodynamics, acoustics and aeroelasticity were seen by all [12][13][14][15]. In addition to propeller flows, HMB3 has also been validated for tiltrotors, including the AW609 and XV-15 [16], for hover and forward flight.…”

A review of propeller stall flutter

“…The use of transition models was seen to have a significant effect on the leading edge separation and, with the transition models of the time utilising empirical coefficients, an improvement was required to enhance the correlation. [20].…”

“…In order to improve the correlation and mitigate the effects of flow reattachment, an investigation was conducted by Higgins et al who utilised resolved flow modelling across aerofoil sections undergoing deep dynamic stall [20]. Quasi-3D simulations of the NACA 0012, 70%R and 90%R Commander blade sections were conducted.…”

“…This investigation used the HMB3 CFD solver and compared the results of URANS and SAS [21] calculations against experimental data. The use of the SAS method for aerodynamic modelling had proven beneficial in a typical two-dimensional form via the study of pitching aerofoils [20]. Such a method allows for a balance between the resolved and statistical content to be found, and improves the accuracy without significantly increasing the computational cost.…”