High Lift Common Research Model for Wind Tunnel Testing: An Active Flow Control Perspective

Abstract

This paper provides an overview of a research and development effort sponsored by the NASA Advanced Air Transport Technology Project to achieve the required high-lift performance using active flow control (AFC) on simple hinged flaps while reducing the cruise drag associated with the external mechanisms on slotted flaps of a generic modern transport aircraft. The removal of the external fairings for the Fowler flap mechanism could help to reduce drag by 3.3 counts. The main challenge is to develop an AFC system that can provide the necessary lift recovery on a simple hinged flap high-lift system while using the limited pneumatic power available on the aircraft. Innovative low-power AFC concepts will be investigated in the flap shoulder region. The AFC concepts being explored include steady blowing and unsteady blowing operating in the spatial and/or temporal domain. Both conventional and AFC-enabled high-lift configurations were designed for the current effort. The high-lift configurations share the cruise geometry that is based on the NASA Common Research Model, and therefore, are also open geometries. A 10%-scale High Lift Common Research Model (HL-CRM) is being designed for testing at the NASA Langley Research Center 14-by 22-Foot Subsonic Tunnel during fiscal year 2018. The overall project plan, status, HL-CRM configurations, and AFC objectives for the wind tunnel test are described.

Investigation of the Nacelle/Pylon Vortex System on the High-Lift Common Research Model

“…The 10%-scale semispan wind-tunnel test model of the CRM-HL was built for wind-tunnel testing. The CRM-HL geometry is open to the public and intended to be used in research and development efforts related to aerodynamic efficiency, noise reduction, high-lift aerodynamics/flow physics, and computational fluid dynamics (CFD) development/validation [5]. The CRM-HL model is representative of a modern civil transport airplane, and the 10%-scale semispan wind-tunnel test model includes both the conventional and AFC-enabled SHL systems.…”

“…As a relevant high-lift geometry, the CRM-HL model can serve as a high-lift technology development platform and the performance levels achieved by the geometry can be a reference for the conventional high-lift systems [6]. Although the main focus of the wind-tunnel test campaign was to assess the feasibility of active flow control on the simplified CRM-HL configuration [5,7,8], the conventional CRM-HL version was also tested to establish a benchmark for the AFC research. The conventional CRM-HL model features a threeelement high-lift configuration that includes a slat, a main wing, and a single slotted Fowler flap [5,6].…”

Numerical Simulation of a Simplified High-Lift CRM Configuration Embedded with Fluidic Actuators

“…28 A 10%-scale high-lift version of the CRM (CRM-HL) based on the geometry of Ref. 28 is being designed and built for wind tunnel testing 29 at the NASA Langley Research Center 14-by 22-Foot Subsonic Tunnel (14×22) during calendar year (CY) 2018. A simple hinged flap geometry with integrated and exchangeable AFC modules was derived from the conventional CRM-HL design.…”

Active Flow Control for Trailing Edge Flap Separation

“…The flap deflection range of the current investigation covers the range being proposed for a larger scale, wind tunnel experiment on a high-lift version of the Common Research Model (CRM). 13 The goal of the small-scale experiments is to investigate methods to improve the input power requirements of the AFC system that will be evaluated on the high-lift CRM. In this paper, we employ surface oil flow visualization and o↵-body measurements using Particle Image Velocimetery (PIV) to investigate the interaction between the SWJ excitation and the shear layer associated with the flow separation.…”