Vortex-Generator Installation Studies on Steady-State and Dynamic Distortion

Abstract

The theoretical and experimental work carried out under the NASA /MOD joint aeronautical program has shown that computational uid dynamics (CFD) vortex-generator installation designs successfully managed inlet-duct ow distortion and that signi cant bene ts in ow unsteadiness at the engine face were also present. The main conclusions to date from the collaborative effort between the NASA Lewis Research Center and the Defence Research Agency in Bedford are as follows: 1) Vortex-generator installations can be designed to be effective over a wide range of inlet operating conditions using CFD and formal optimization procedures, 2) reductions in steady-state engine face distortion of up to 80% have been measured in the M2129 inlet S-duct using CFD-designed vortex-generator installations, 3) reductions in ow unsteadiness of up to 80% have been measured in the M2129 inlet S-duct using CFD-designed vortex-generator installations, and 4) the reduced Navier-Stokes code RNS3D is a useful tool to design vortex-generator installations to manage engine-face distortions over a wide range of inlet operating conditions. NomenclatureA = ow area c = vortex-generator chord length D = diameter DC60 = circumferential total-pressure distortion descriptor d = vortex-generator lateral spacing h = vortex-generator blade height M = Mach number Pt = total pressure Pt av = average total pressure Pt max = maximum ring total pressure Pt min = 60 deg-sector minimum ring total pressure Pt 0 = freestream or reference total pressure Q = face-average dynamic pressure R = radial distance X = axial distance from inlet throat vg = vortex-generator spacing angle vg = vortex-generator incidence angle ef = dimensionless engine-face radial distance * = displacement thickness s = installation sector angle Subscripts ef = engine face i = inlet-throat station ring = ring rms = total pressure RMS value sep = separation Received April 3, 1996; presented as Paper 96-3279 at the AIAA / ASME /SAE/

Passive Flow Control Study in an S-Duct Using Stereo Particle Image Velocimetry

“…VG2 total pressure flow field (Fig. 9c) is similar to that reported by Anderson et al [22] Jirasek [29] where the total pressure losses are located near the wall at the top sector of the AIP. For VG1 and VG2, the increase of the extent covered by the VGs ( ) from 67.5˚ to 97.5˚ moves the loss region toward the upper periphery of the AIP.…”

“…A reduction in DC60 of up to 80% at the AIP was achieved with a VG height ℎ = 0.58 , a VG centerline axial position at 2R in from the inlet and a number of VGs of 22 covering a circumferential sector of 157.5˚. The comparison of the numerical and experimental data [22] showed the corotating VG configuration was used to redistribute the low energy flow uniformly around the periphery of the engine face leaving a high energy central region.…”

“…A number of previous studies have investigated the use of passive flow control to reduce the steady distortion at the AIP for both rectangular [17][18][19] and circular ducts [11,[20][21][22][23]. Generally, in the form of arrays of co-rotating vortex generators (VGs), passive flow control devices are used to modify the secondary flows inside the duct.…”

CFD Validation and Flow Control of RAE-M2129 S-Duct Diffuser Using CREATETM-AV Kestrel Simulation Tools

“…Though these devices are very simple to install, they cannot effectively control and reduce distortion at all off-design conditions. Anderson and Gibb [11] presented the experimental results of applying different vortex generator configurations for the secondary flow control of the M2129 S duct. The experiments were again conducted at the DRA/Bedford 13 ft × 9 ft wind tunnel with the throat Mach number in range of 0.2 to 0.8.…”

“…The recent applications of these devices attempt to improve both total pressure recovery and uniformity. In these applications, an array of vane type vortex generators are typically placed at or behind the first bend to control the secondary flow formation [11]. Though these devices are very simple to install, they cannot effectively control and reduce distortion at all off-design conditions.…”