Intake ground vortex characteristics

Abstract

The development of ground vortices when an intake operates in close proximity to the ground has been studied computationally for several configurations including front and rear quarter approaching flows as well as tailwind arrangements. The investigations have been conducted at model scale using a generic intake geometry. Reynolds Averaged Navier–Stokes calculations have been used and an initial validation of the computational model has been carried out against experimental data. The computational method has subsequently been applied to configurations that are difficult to test experimentally by including tailwind and rear quarter flows. The results, along with those from a previous compatible study of headwind and pure cross-wind configurations, have been used to assess the ground vortex behaviour under a broad range of velocity ratios and approaching wind angles. The characteristics provide insights on the influence of the size and strength of ground vortices on the overall quality of the flow ingested by the intake.

Intake ground vortex and computational modelling of foreign object ingestion

“…For a converged solution minimum static pressure convergence level was in the order of at least 10 -5 . Previous studies have examined the ability of CFD to calculate the key aerodynamic aspects associated with the ground vortex such as the vortex strength (11,12) . These studies showed that the vortex circulation was calculated within typically 13% of the measured data across a range of velocity ratios and flow yaw angles.…”

“…When an intake operates in close proximity to the ground, there can be a notable interaction between the intake aerodynamics and the surface. The mechanisms and characteristics of ground vortices has been studied both experimentally (3)(4)(5)(6)(7)(8)(9)(10) and computationally (11)(12)(13) . Overall these studies showed that the ground vortex can form under headwind, crosswind as well as quiescent conditions.…”

“…In the context of practical aircraft operations, the vorticity is also affected by ambient gusts, other aircraft, buildings, and the fuselage which all combine to deteriorate the uniformity of the intake flowfield (14) . Although the ground vortex (GV) formation mechanism is complex (4,12) , the formation threshold and vortex strength are predominately The AeronAuTicAl JournAl SepTember 2015…”

“…Computational studies have also been performed to assess the GV characteristics for a range of configurations including engine test cells (13) as well as for full aircraft configurations (19) . Zantopp (11) and Mishra (12) undertook a range of computational studies to simulate the experimental work of Murphy (8,9,15) . The work comprised both Reynolds averaged Navier-Stokes (RANS) and unsteady RANS simulations and encompassed a range of configurations for velocity ratio, ground clearance, and intake yaw angle.…”

“…Although previous publications have assessed the details of the GV aerodynamics (8,9,(11)(12)(13)15) , it is of interest to consider some of these aspects within the context of GV and FOI. Of particular importance is the vortex strength, as characterised by Γ*, the vortex position as well as the magnitude and extent of the local static pressure deficit at vortex core.…”