An experimental rig to investigate crosswind effects on intake flow behaviour
type: CreativeWork
description: Aerospace design engineers are being pushed to invent greener and more efficient technology. The next generation of turbofan engines aims to drastically reduce their carbon emissions by improving propulsive efficiency. To accomplish this low fan pressure ratio, large engine technology has been developed. These new fans require slimmer and sharper, lower drag and weight intakes, which are at risk of experiencing boundary layer separation under aerodynamically difficult conditions. One particularly problematic condition is the crosswind experienced during runway operations, which can lead to downstream distortion of the flow at the fan plane. Due to the complex nature of the ingested crosswind flow field, it has been found to be difficult to study in detail experimentally without incurring extreme costs. The work in this thesis presents a method of studying nearside intake physics under strong crosswind and high-engine power conditions in quasi-two dimensions. This allows for unprecedented optical access at Reynolds numbers previously only obtained at high-cost facilities or full-scale engine testing. The rig functions via the use of three unique and controllable flow paths, allowing for some emulation of variations in crosswind speeds and engine power settings. A design process was conducted to match the pressure gradient that the intake would experience under a 25-knot crosswind and high engine power setting. The rig was de-risked using RANS computations before it was commissioned, establishing a baseline flow field with an attached shock wave-boundary-layer interaction present at the highlight. From this baseline, rig parameters were varied to test the experimental range of the rig, achieving all canonical crosswind flow fields and finding that shock-induced separation did not occur until a peak isentropic Mach number of 1.44 was present on the intake, beyond the usual limit for an attached interaction. Separation unsteadiness was also discovered on the boundary be…
abstract: Aerospace design engineers are being pushed to invent greener and more efficient technology. The next generation of turbofan engines aims to drastically reduce their carbon emissions by improving propulsive efficiency. To accomplish this low fan pressure ratio, large engine technology has been developed. These new fans require slimmer and sharper, lower drag and weight intakes, which are at risk of experiencing boundary layer separation under aerodynamically difficult conditions. One particularly problematic condition is the crosswind experienced during runway operations, which can lead to downstream distortion of the flow at the fan plane. Due to the complex nature of the ingested crosswind flow field, it has been found to be difficult to study in detail experimentally without incurring extreme costs. The work in this thesis presents a method of studying nearside intake physics under strong crosswind and high-engine power conditions in quasi-two dimensions. This allows for unprecedented optical access at Reynolds numbers previously only obtained at high-cost facilities or full-scale engine testing. The rig functions via the use of three unique and controllable flow paths, allowing for some emulation of variations in crosswind speeds and engine power settings. A design process was conducted to match the pressure gradient that the intake would experience under a 25-knot crosswind and high engine power setting. The rig was de-risked using RANS computations before it was commissioned, establishing a baseline flow field with an attached shock wave-boundary-layer interaction present at the highlight. From this baseline, rig parameters were varied to test the experimental range of the rig, achieving all canonical crosswind flow fields and finding that shock-induced separation did not occur until a peak isentropic Mach number of 1.44 was present on the intake, beyond the usual limit for an attached interaction. Separation unsteadiness was also discovered on the boundary be…
author: Dickinson, Luke
keywords: Aerodynamics, Crosswind, Engineering, SBLI
license: https://www.repository.cam.ac.uk/bitstreams/77cea115-b591-45dc-b920-8edcfed3f6ef/download
license: http://purl.org/NET/rdflicense/allrightsreserved
date published: 2024-09-26
date modified: 2026-07-24T01:33:15Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.119075