Validation of Helicopter Flow Predictions Using Wind Tunnel LDA Measurements
Abstract
Helicopter engine exhaust plumes can constitute a large contribution to the total platform infra-red (IR) signature. The flow around such vehicles is particularly complex and an accurate representation of the plume is essential for high fidelity prediction of the IR signature. CFD techniques are well documented and have long been used for the generation of airflow and thermodynamic data. However, validation is essential for any problem to which the techniques are applied. Dstl uses the PHOENICS CFD code for the modelling of aircraft flow fields. In conjunction with PHOENICS, the SAPPHIRE modelling suite has been developed to aid model generation and IR signature analysis of air platforms. This paper reports on the ability of SAPPHIRE to accurately predict the interaction of an exhaust plume with downwash caused by a helicopter rotor. Laser Doppler Anemometry (LDA) has been used to measure the flow around a simplified wind tunnel model orientated such that the free stream simulates the downwash. Comparison of this data with CFD results shows good general correlation and gives confidence that a 'fit for purpose' solution can be generated. Possible reasons for the discrepancies have been identified and are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2002
- Accession Number
- ADP023096
Entities
People
- David Gatland
- Lee Hayward
- Steve Rooks