Computational Study of Afterbody Effects for the Joint Direct Attack Munition (JDAM)
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFS TN
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Computational analysis of a JDAM in the Minfinity 0.9 to 1.4 flow regime determined the effect of changes to the store afterbody and support sting on store loads. The computational results compared well to three sets of wind tunnel data. Accuracy requirements necessitated both that the store geometry be modeled with exceptional detail, and that the Navier-Stokes equations with the Nichols k-Epsilon turbulence model be employed. Comparisons to measured data showed excellent agreement with aerodynamic load increments and also with the absolute values of the loads. Analysis using a wall function model for the boundary layer also compared well with data. The comparisons established a sufficient level of confidence in the numerical model as to allow its use in determining the forces and moments free of support effects at the flight Reynolds number.
- Fluid Mechanics
- Guided Munitions