Our customer is a Defence establishment engaged in modification of their multi-barrel artillery rockets for longer range. It would require the rockets to attain higher Mach numbers and therefore, higher spin rates. The customer resolved the corresponding issues of lower static margin and higher Magnus forces by redesigning the stabilizer fin design. They engaged Zeus Numerix for aerodynamic evaluation of candidate fin design using CFD.
It was expected that the difference in aero coefficients between some of the candidate fin designs may turn out to be very small. Therefore, a simulation approach was adopted where contribution from numerical uncertainties like mesh distribution, turbulence model and convergence criteria were minimized. Zeus Numerix opted for structured multi-block mesh generation for a precise control on mesh distribution and refinement. Proprietary compressible solver was used for bulk simulations that exploited parallel computers for quick turnaround time.
Customer was provided a thorough analysis of CFD results for detailed discussion on aerodynamic aspect of candidate fin designs. Variation of sensitive aerodynamic parameters such as roll moment and Magnus forces were keenly monitored. Appropriateness of selected fin design was confirmed during successful launch of this long range artillery rocket.