A Unit-Problem Investigation of Blunt Leading-Edge Separation Motivated by AVT-161 SACCON Research

A research effort has been initiated to examine in more detail some of the challenging flow fields discovered from analysis of the SACCON configuration aerodynamics. This particular effort is oriented toward a diamond wing investigation specifically designed to isolate blunt leading-edge separation phenomena relevant to the SACCON investigations of the present workshop. The approach taken to design this new effort is reviewed along with the current status of the program

A Reduced-Complexity Investigation of Blunt Leading-Edge Separation Motivated by UCAV Aerodynamics

A reduced complexity investigation for blunt-leading-edge vortical separation has been undertaken. The overall approach is to design the fundamental work in such a way so that it relates to the aerodynamics of a more complex Uninhabited Combat Air Vehicle (UCAV) concept known as SACCON. Some of the challenges associated with both the vehicle-class aerodynamics and the fundamental vortical flows are reviewed, and principles from a hierarchical complexity approach are used to relate flow fundamentals to system-level interests. The work is part of roughly 6-year research program on blunt-leading-edge separation pertinent to UCAVs, and was conducted under the NATO Science and Technology Organization, Applied Vehicle Technology panel

Numerical and Theoretical Considerations for the Design of the AVT-183 Diamond-Wing Experimental Investigations

A diamond-wing configuration has been developed to isolate and study blunt-leading edge vortex separation with both computations and experiments. The wing has been designed so that the results are relevant to a more complex Uninhabited Combat Air Vehicle concept known as SACCON. The numerical and theoretical development process for this diamond wing is presented, including a view toward planned wind tunnel experiments. This work was conducted under the NATO Science and Technology Organization, Applied Vehicle Technology panel. All information is in the public domain

Stability and Control Investigations of Generic 53 Degree Swept Wing with Control Surfaces

A contribution for the assessment of the static and dynamic aerodynamic behavior of a generic unmanned combat air vehicle configuration with control devices using computational fluid dynamics methods is given. For the study, various computational approaches have been used to predict stability and control parameters for aircraft undergoing nonlinear flight conditions. For the computational fluid dynamics simulations, three different computational fluid dynamics solvers are used: the unstructured grid-based solvers DLR TAU code and USM3D from NASA, as well as the structured grid-based National Aerospace Laboratory/NLR solver ENSOLV. The numerical methods are verified by experimental wind-tunnel data. The correlations with experimental data are made for static longitudinal/lateral sweeps and at varying frequencies of prescribed roll/pitch/yaw sinusoidal motions for the vehicle operating with and without control surface deflections. Furthermore, the investigations should support the understanding of the flow physics around the trailing-edge control devices of highly swept configurations with a vortex-dominated flowfield. Design requirements should be drawn by analyzing the interaction between the vortical flow and the control devices. The present work is part of the North Atlantic Treaty Organization’s Science and Technology Organization/ Applied Vehicle Technology Task Group AVT-201 on stability and control prediction methods´

STATIC AND DYNAMIC NUMERICAL SIMULATIONS OF A GENERIC UCAV CONFIGURATION WITH AND WITHOUT CONTROL DEVICES

In this chapter, the prediction capabilities of high-fidelity, Reynolds-averaged Navier-Stokes based CFD methods of the flowfield and aerodynamic behaviour of the SACCON configuration with control devices will be shown. The report starts with the prediction of the flow physics of the clean configuration (BL-no flap deflection), followed by a comparison between different control surface settings and the Baseline (BL) configuration without flap deflection. The differences between numerical simulations and experimental data will be discussed as well as sensitivities regarding the numerical approach, regarding the CFD method and applied turbulence models. Finally, comparisons between numerical and experimental simulations of dynamic pitch manoeuvres will be presented and discussed