A CFD study on the strut interference on a regional aircraft wind-tunnel model

Abstract

The aim of this paper is to investigate the aerodynamic interference effects of typical devices supporting aircraft models during wind tunnel tests by means of CFD tools. This work proposes the use of steady RANS simulations of the flow field in order to predict the interference produced by two different models of struts: (1) one that is made up of two parts and is solidal with the wind-tunnel model for variation of the angles of incidence (α) and of the angles of sideslip (β) and (b) the second that is made up of one part and is fixed for α variations and is solidal with the model for β variations. Low and high Reynolds flow conditions are considered and a typical cruise configuration of a scaled model of regional aircraft is addressed in both power-off and power-on conditions. The strut effect is investigated for several angles of incidence and sideslip. From the numerical point of view, the flow field and forces disturbance caused by the struts are derived by comparing simulations with and without the support. The interference is analysed in terms of global forces and moments coefficients and local quantities, such as pressure coefficients distributions. The main result regarding the comparison between the two models of strut is that the corrections to be applied to experimental data and the effect of both ventral struts on the global aerodynamic forces and moments are small.