A fluid structure coupling of the Ariane-5 nozzle section during start phase by detached eddy simulation

Abstract

Concerning the requirements of future rocket technologies, providing a cost-efficient access to orbit as well as an increase in system reliability, a deeper insight into the unsteady phenomena during ascent of modern launchers is essential. Unsteady interactions and resonances of the turbulent separated launcher wake and the nozzle structure play an important role for the design of future main stage propulsion systems. The so-called buffeting coupling phenomenon is one of the main challenges during ascent. In the present study, a coupled simulation of the afterbody of the Ariane-5 launcher with a realistic structural and aerodynamic representation of different nozzle configurations is carried out. On the computational fluid dynamics side, unsteady detached eddy simulations are coupled with structural computations for different nozzle configurations. The essential features of the interaction process are well captured. The coupling algorithm is validated by a nonlinear supersonic panel flutter simulation with highly transient mechanical interaction.

Experimental study of the boosters impact on the rocket aerodynamic characteristics

“…It should be noted here that, once validated (by experimental results), CFD methods are invaluable in the analyses of various modifications to the rocket configuration (including attached bodies, such as the boosters), and in many cases, they can replace experimental research. The use of CFD for rockets aerodynamic characteristic was widely described in the literature (Lopez et al , 2013; Luedeke and Calvo, 2009; Rasuo et al , 2015; Rogers et al , 2015).…”

Control of Ideally Expanded and under Expanded Nozzle Flows with Micro Jets

“…The investigations have demonstrated the origin of these unsteady phenomena at the base of the nozzle are 1) asymmetric separation line, 2) pressure pulsations at the separation and reattachment locations, 3) aeroelastic coupling, 4) transition of separation pattern between restricted shock separation (RSS) and full shock separation (FSS), and 5) external flow instabilities such as buffeting [9]. A computational approach to model the fluid-structure interactions of the one such nozzle using detached-eddy simulations coupled with second-order structural computations for different nozzle configurations has been studied [10].…”

Effects of Shear-Layer Reattachment on the Nozzles of a Launch Vehicle

“…Addressing the problem in the context of the Ariane 5 launch vehicle as base-flow buffeting, review of experimental results to determine the effects of 1) geometric effects, 2) jet on and off, 3) yaw angle, and 4) incidence angle in addition to M ∞ , Re, etc., has been reported [10]. A computational approach to model the fluidstructure interactions of the same nozzle using detached-eddy simulations coupled with second-order structural computations for different nozzle configurations is reported in [11]. Noting that transonic Mach numbers pose the biggest problems, detailed experimental results involving large numbers of unsteady pressure measurements and particle image velocimetry studies on a scaled model of the Ariane 5 rocket have been reported in [11].…”

“…A computational approach to model the fluidstructure interactions of the same nozzle using detached-eddy simulations coupled with second-order structural computations for different nozzle configurations is reported in [11]. Noting that transonic Mach numbers pose the biggest problems, detailed experimental results involving large numbers of unsteady pressure measurements and particle image velocimetry studies on a scaled model of the Ariane 5 rocket have been reported in [11]. Using proper orthogonal decomposition methods to correlate between pressure fluctuations and velocity fluctuations, vortex shedding from booster lower motor attachments (dispositif d'accrochage arriere, or rear shackles/DARR struts of circular cross section holding the strap-on rockets to the core at the base has been identified as the root cause for buffet excitation of the nozzle, as reported in [12].…”