Transonic Tail Buffet Simulations for the Common Research Model

Abstract

In advance of the ESWI RP measurement campaign in the European Transonic Wind Tunnel in 2014, numerical simulations for NASA's Common Research Model were performed using the DLR TAU code. The presented investigations are focused on the interaction between the separated flow of the main wing with the horizontal tail plane at high Mach numbers. This phenomenon, called transonic tail buffet, poses a serious risk and therefore limits the flight envelope for commercial aircraft.A mesh for the CRM was built including a high resolved tetrahedral block to reduce dissipative effects in the wake. A validation was conducted which shows excellent agreement to the results of the Drag Prediction Workshops. Based on lift polar simulations the buffet onset regime was defined and an inflow condition beyond this point was selected to perform an unsteady simulation. It is shown that a corner separation leads to a movement of the complex shock system on the upper surface of the main wing. Large vortices are shed which propagate downstream and massively influence the flow around the HTP followed by a high frequency response which is found in all integral coefficients. Nomenclatureangle of the HTP [ • ] M Mach number [−] p pressure fluctuations [N/m 2 ] q ∞ dynamic pressure [N/m 2 ] Re Reynolds number [−] xyz cartesian coordinates [m] α angle of attack [ • ] η dimensionless span coordinate [−] ν t eddy viscosity [m 2 /s] Downloaded by CORNELL UNIVERSITY on July 30, 2015 | http://arc.aiaa.org |

Delayed Detached–Eddy Simulation of Shock Buffet on Half Wing–Body Configuration

“…17 A similar conclusion was drawn from the first Aeroelastic Prediction Workshop, 18 where RANS simulations were shown to be insufficient for the correct physical modelling of the shock-induced vibration on a flexible wing. However, promising results have presented the capability of URANS to simulate transonic tail buffet on a wing-body-tail model for a wide range of angles of attack, 19 reproduced the shock motions on simple three-dimensional configurations, 20 or described the transonic buffet phenomenon on a half wing-body configuration at different flow conditions. 21,22 At the same time, high-fidelity approaches are becoming more and more popular in the aeronautical field and have successfully been applied to other configurations.…”

Prediction and Measurement of the Common Research Model Wake at Stall Conditions

“…The resulting wake spectrum is broadband and does not show the distinct tonal content known from the two-dimensional (2-D) buffet [1]. Although detailed numerical and experimental research on 2-D buffet has been performed, few studies on buffet, shock-induced separation, and wake development past 3-D aircraft have been published so far [1][2][3][4].…”

Installation aerodynamics of civil aero-engine exhaust systems

“…The airframe used in this study is the NASA Common Research Model (CRM) which was designed to represent a wide body civil transport aircraft capable of carrying 250-300 passengers [32]. Specically, the wing/body/horizontaltail geometry [33] [34,35]. A lift coecient of 0.5 was selected as this is the nominal design condition of the CRM airframe [32].…”