BQM-74 Target Aerodynamics Performance Analysis Support
Investigators
D.
Findlay, L. Hoffman, and R. Anderson, U. S. Naval Air Warfare Center (NAWCAD)
Application Overview
It is
not uncommon for the U.S. Navy Fleet to require vehicle performance in roles beyond those
anticipated in the initial design. In these instances, additional aerodynamic performance
information is required to evaluate changes in vehicle performance and associated mission
capabilities. The BQM-74 aerial target is a recent example of this, in which additional
wing tip dual pods were added to the baseline configuration. The new pods increase
aerodynamic drag and affect mission range. The objective of the present study is to
demonstrate the utility of an overset grid approach in rapidly providing accurate
performance data for such modifications to existing fleet vehicles.
Methodology
The
overset structured grid generation tools and flow solver software being developed through
the CHSSI CFD CTA was adopted in this work. The use of an overset grid approach is well
suited to this type of analysis. The existing overset grid system for the BQM-74 aerial
target is easily modified to reflect the design change. Only the grid components
associated with the change need to be replaced. All other grid components are completely
reusable.
Results (8/31/97)
The OVERFLOW-D code is used to simulate the steady viscous flow about the baseline and modified configurations of the BQM target (see figure). The increase in drag caused by the wing tip mounted pods is accurately predicted in the simulations. Simulation results were presented to the program office to establish confidence in CFD capability to provide accurate and timely predictions of contemplated configuration modifications of existing fleet vehicles.
Launch of BQM-74 aerial target
Significance
Improved analysis capability of this type translates to reduced cost to
the program office by reducing the need for expensive wind tunnel and flight tests.
Additional benefit is recognized in an ability to influence the design of vehicle
modifications contemplated in the future.
References
1. Meakin, R., "Composite Overset
Structured Grids," in Handbook of Grid Generation, ed.
J. Thompson, N. Weatherill, and B. Soni, CRC Press, Inc., Boca Raton, FL, 1997.
Figure 1. Launch of
BQM-74 aerial target.
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(a)
(b)
Figure 2. Predicted
surface pressure distributions.
(a) Baseline configuration. (b) With dual wing-tip pods.
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