Aerodynamics of dual facesheet acoustic liners

This thesis presents an in-depth investigation of the consequences of adding a second facesheet on the aerodynamic performance of acoustic liners. This is done by performing pore-resolved Direct Numerical Simulations (DNS) of a channel flow at Reτ = 500. Simulations are conducted for various dual facesheet configurations, exploring different...

Investigating Foaming Materials in 3D Printing: An Application for Motorcycle Helmets

This thesis investigates novel foaming materials for fused deposition modelling (FDM) which have been introduced in 2019. The materials are able to foam by the addition of foaming agents. Foaming materials for FDM printing can be advantageous since they can create lightweight models, and have good impact strength and toughness in relation to...

Aeroacoustics of Jet-Surface Interaction and Passive Solutions for Mitigating Jet-Installation Noise

Aircraft noise levels have been significantly reducedwith the introduction of high-bypass ratio turbofan engines, particularly jet noise due to turbulence mixing. This, however, has led to engines with larger diameters and a closer coupling between them and the airframe. As a result, interactions between the exhaust jet flow and the wing give...

Acoustic liners for jet-installation noise reduction

A Helmholtz resonator with a curved cavity is studied for reducing jet-installation noise in a configuration comprised by a subsonic jet and a nearby flat plate. The face-sheet and cavity are designed with the Guess method and the impedance is verified through an experiment and a simulation of an impedance tube. Both single and double degree...

Aero-acoustic response of an acoustic liner

In this thesis, the resistance of a single degree of freedom liner is investigated experimentally. Semi-empirical resistance modelling fails at higher Mach numbers (M₀>0.3) and sound pressure levels (SPL>130dB), and experimental work is missing in these conditions. An experiment combining in-situ impedance measurements and phase...

Equivalent Fluid Modelling of a Honeycomb Acoustic Liner using the Acoustic Porous Medium Formulation

Over the past decades, numerous methods have been used to study acoustic liners through their impedance, of which numerical methods are of particular interest. Despite their advantages, numerical methods are bounded by certain drawbacks. One such drawback stems from the need to accurately discretize the liner geometry, which can lead to large...

Lower limb prosthesis liner design for amputees with diabetes

This project investigates the needs of diabetic and vascular amputees to establish design criteria for a new lower-limb prosthesis liner specifically for diabetes and vascular patients. Initially, a literature review was conducted to investigate liner material properties and outcomes during use, as well as how often diabetic and older amputees...

Multidimensional examination of the performances of a liner shipping network: trunk line/route operated by conventional (Panamax Max) and mega (ULC - ultra large container) ships

This paper deals multidimensional examination of performances of a trunk line/route of liner container-shipping network serving an intercontinental supply chain by the conventional (Panamax Max) and mega (ULC - Ultra Large Container) ships. The trunk line/route of the network includes the supplier and the customer seaport of freight shipments...

Design of a cooling helmet liner

Humans wear helmets to protect the head from impact. However, covering part of the body influences the thermal balance due to restricting the heat loss capacity. This is especially the case for the head due of the lack of vasoconstriction response in the head’s skin. This project focussed on improving thermal comfort and perception when wearing...

An Analysis of Index-Linked Contract as a Solution to Shippers - Carriers Contractual Issues in Container Liner Trade

Containerization has emerged as the favourable method in ocean transport as it is able to transport cargoes worldwide with low cost. Liner service is the concept which develops as the concept that provides scheduled transport service. At the latter development, it also provides intermodal service which combine ocean and inland transportation....

Local Buckling Behaviour of a Corrosion Resistant Alloy Liner in Tight Fit Pipe due to Axial Compression

A promising possibility to reduce corrosion resistant pipeline costs is the concept of Tight Fit Pipe, which is a double wall pipe where a Corrosion Resistant Alloy liner is mechanically fitted inside a carbon steel outer pipe. The mechanical bonding of the Tight Fit Pipe is made through a thermohydraulic manufacturing process. Problem...