Citation:
Khanal B, Knowles K, Saddington AJ. (2009) Computational study of cavity flowfield at transonic speeds. In: 47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition 2009, pp. 701-719
Abstract:
In this paper, the results of a computational study on the unsteady flow
features in three-dimensional empty cavities and a cavity with a store are
presented. Flow simulations with a turbulence model based on a hybrid method,
which behaves as a standard RANS model within the attached boundary layer and as
a LES Sub-Grid Scale model in the rest of the flow, including the separated
regions, are used in this study. The time-mean flow study showed the existence
of spanwise flow in the 3D cavity. In the unsteady flow study, computed near-
field acoustic spectra were for empty cavity as well as cavity-withstore cases.
Unsteady results from an empty cavity case are compared with experimental data
and the frequency of the dominant mode is in good agreement with the experiment.
Study of unsteady pressure spectra for the cavity-with-store case found the
presence of many peaks and the corresponding mode frequencies were found to
agree well with the Rossiter modes. The mean flowfield visualisation for the
cavity-with-store case clearly showed that the mean flowfield was effectively
divided into two halves with signifiant reduction of the spanwise flow across
the cavity width. This blockage effect of store and strut on the spanwise flow
is thought to have reduced the interaction, and subsequent non-linear coupling
between, the Rossiter modes. This may be the reason for the coexistence of
multiple modes without the coupling among them.
