Lift Losses for Fin-Body Gaps in Transonic and Supersonic Speeds: Data Correlation and Modeling
Abstract
An algebraic model is established to predict fin lift losses due to fin-body gaps for missiles and projectiles in transonic and supersonic speeds. The model is based on 2 distinct correlations which were established using wind tunnel results. The first correlation is for transonic speeds (0.8< M <1.2) and for large fin gap heights (g/D > 0.08). This extends the Author's earlier work which was valid only for gap heights, /D < 0.08. The 2nd correlation is for both small and large gaps at supersonic speeds (1.2 < M<4). Both correlations use the physical parameters of the fin as well as the flow conditions. Results obtained using these correlations are very satisfactory when compared with the data that they represent. The correlations cover all shapes of fin planforms with moderate aspect ratios (0.5 to 4.0) and all heights of streamwise gaps. A factor which represents the effects of the fin in producing lift (normal force for the body- fin combination) in the presence of a finbody gap is computed. This factor provides a direct estimate of the fin lift losses which, in turn, is to be used to determine the static stability of the missile or finned projectile. The present model includes viscosity and fin support interference effects based on actual wind tunnel measurements which encompass both effects. The present analysis uses very simple algebraic models which can be easily implemented in any fact aerodynamic prediction code for missiles and projectiles. Accuracy of the model is + or - 7.0% based on all the cases considered.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1989
- Accession Number
- ADA212267
Entities
People
- Ameer G. Mikhail
Organizations
- Ballistic Research Laboratory