Safe separation and accurate delivery of stores on a target are of primary concern to the military. In the flow fields of modern high-speed aircraft, it cannot be assumed that a store will not collide with the aircraft or separate smoothly enough to control the trajectory.

CFDRC develops computational technologies and provides CFD consultation services for store separation aerodynamics analysis and design support. Coupled high fidelity CFD, 6-DOF and prescribed motion technology was developed by CFDRC to handle the aerodynamics and body dynamics of complex multi-moving body configurations. This technology has been incorporated into the CFD-FASTRAN code. Some examples of our store separation work are provided below.

CFDRC engineers used CFD-FASTRAN for the time accurate simulation of this F-16 with multiple bombs carried on a rack mounted under the wing. The objective of the simulation was to calculate the trajectory of the bomb as it separate from the rack and assess its potential collision with the fuel tank.

Click image for movie

CFDRC engineers participated in the U.S. Navy CFD challenge to predict the viscous flow fields of a JDAM store separating from the F/A-18 aircraft. CFD-FASTRAN was used to calculate the steady state captive loads on the aircraft and stores. Time accurate simulations were also conducted to calculate the trajectory of the JDAM as it separates from the aircraft.

This Air Force Eglin Wing/Pylon/Finned Store configuration is a benchmark test case commonly used in the industry for 6-DOF models validation. This test case was used to validate CFD-FASTRAN's moving body capabilities. As seen on the right, the trajectory results show excellent comparison to test data.

Click image for movie