An Investigation of V/STOL Jet Interactions in a Crossflow
Abstract
Recently, a numerical simulation code was developed to study the interaction of the effects of a row of normal impinging jets. This model essentially simulates the hovering configuration of a V/STOL aircraft. The code solves unsteady, 3-D incompressible Navier-Stokes equations using the technique of large-eddy simulations which resolves all the length scales above the grid resolution and models the contribution of the small scales by a subgrid eddy viscosity model. The present study extends this code to include other realistic V/STOL configurations such as an obliquely impinging jet and an impinging jet in crossflow with and without a moving ground plane. These configurations model the V/STOL aircraft in pitch and in forward motion. These modifications were successfully achieved and preliminary simulations using axisymmetric forcing of the impinging jet were carried out to demonstrate the capability of the numerical code. Even with coarse mesh simulations, the results show good qualitative agreement with experimental observations. Simulation of the impinging jet in crossflow showed the formation of counterrotating streamwise vortices which has been observed in many experiments. However, it was shown that the presence of the adjacent impinging jet (which is absent in all experiments) can significantly modify the dynamics of the vortical motion in the flow field. Significant 3-dimensional vortex stretching occurs in this flow and redistribution of the total vorticity in the flow field occurs in a complex manner. Phase I results indicate that a numerical simulation capability now can be used to understand the dynamics of a variety of V/STOL flight configurations in ground effect in a systematic manner.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1989
- Accession Number
- ADA206360
Entities
People
- Suresh Menon