Blar i NTNU Open på forfatter "Dawson, James"
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A scanning particle tracking velocimetry technique for high‑Reynolds number turbulent flows
Kozul, Melissa; Koothur, Vipin; Worth, Nicholas; Dawson, James (Journal article; Peer reviewed, 2019)We propose a novel robust 3D particle tracking technique based on a scanning laser setup. The method yields Lagrangian statistics in densely seeded turbulent flows with good spatial and temporal resolution, overcoming some ... -
A scanning particle tracking velocimetry technique for high‑Reynolds number turbulent flows
Kozul, Melissa; Koothur, Vipin; Worth, Nicholas; Dawson, James (Journal article; Peer reviewed, 2019)We propose a novel robust 3D particle tracking technique based on a scanning laser setup. The method yields Lagrangian statistics in densely seeded turbulent flows with good spatial and temporal resolution, overcoming some ... -
Acoustic-Convective Interference in Transfer Functions of Methane/Hydrogen and Pure Hydrogen Flames
Æsøy, Eirik; Aguilar, Jose; Bothien, Mirko R.; Worth, Nicholas; Dawson, James (Peer reviewed; Journal article, 2021)We investigate the occurrence and source of modulations in the gain and phase of flame transfer functions (FTF) measured in perfectly premixed, bluff body stabilized CH4=H2 and pure H2 flames. The modulations are shown to ... -
Aerodynamic Development of DNV GL Fuel Fighter - Towards Shell Eco Marathon 2015
Nguyen, Myselie (Master thesis, 2015)Shell Eco Marathon (SEM) is an international engineering competition for university students. The aim of the competitions is to build a vehicle that achieves the highest possible energy efficiency. DNV GL Fuel Fighter is ... -
Aerodynamically driven rupture of a liquid film by turbulent shear flow
Kozul, Melissa; Costa, Pedro S.; Dawson, James; Brandt, Luca (Peer reviewed; Journal article, 2020)The rupture of a liquid film due to coflowing turbulent shear flows in the gas phase is studied using a volume-of-fluid method. To simulate this multiphase problem, we use a simplified numerical setup where the liquid film ... -
An experimental study of a transversely forced round jet
Dalton, Michael Amund Enger (Master thesis, 2014)It has been well established that an interaction between combustion and acoustics can produce self-sustained acoustic oscillations. In recent years, thermo-acoustic instabilities have been a hot research topic, mainly ... -
An Experimental Study of the Jet in Cross-Flow in Fully Developed Turbulent Channel-Flow
Knutsen, Anna Nina (Master thesis, 2015)In this study a transient air jet in a fully developed turbulent channel flow has been studied. The main objective has been to see how the behaviour of the jet has been effected by the turbulent channel flow. The flow in ... -
Assessment of the LES-FGM framework for capturing stable and unstable modes in a hydrogen / methane fuelled premixed combustor
Ho, Jen Zen; Jella, Sandeep; Talei, Mohsen; Bourque, Gilles; Indlekofer, Thomas; Dawson, James (Peer reviewed; Journal article, 2023)The main objective of this paper is to assess the capability of compressible Large Eddy Simulations (LES) to capture azimuthal combustion instability. The thickened flame model coupled with Flamelet Generated Manifold (FGM) ... -
Asynchronous and synchronous quenching of a globally unstable jet via axisymmetry breaking
Kushwaha, Abhijit; Worth, Nicholas; Dawson, James; Gupta, Vikrant; Li, Larry (Peer reviewed; Journal article, 2022)We explore experimentally whether axisymmetry breaking can be exploited for the open-loop control of a prototypical hydrodynamic oscillator, namely a low-density inertial jet exhibiting global self-excited axisymmetric ... -
Characterisation of flame surface annihilation events in self excited interacting flames
Worth, Nicholas; Dawson, James (Journal article; Peer reviewed, 2018)This paper investigates the non-linear flame dynamics of two interacting, premixed, V-shaped flames by characterising the two-dimensional topology of flame annihilation events when the separation distance, S, between them ... -
Characteristics of self-excited spinning azimuthal modes in an annular combustor with turbulent premixed bluff-body flames
Mazur, Marek; Nygård, Håkon Tormodsen; Dawson, James; Worth, Nicholas (Journal article; Peer reviewed, 2018)In this paper we investigate self-excited azimuthal modes in an annular combustor with turbulent premixed bluff-body stabilised flames. Previous studies have shown that both swirl and equivalence ratio influence modal ... -
Coupled Experiments and CFD Simulations for Validation and Improvement of Empirical Coantact Angle Models for Sloshing in Microgravity
Bragstad, Kjersti Elise Baardvik (Master thesis, 2021)Denne masteroppgaven skisserer teorien bak fluiders oppførsel i mikrogravitasjonsmiljøer og foreslår en metode for bakkebaserte eksperimenter for å forstå effekten av kontaktvinkler og overflatespenning på væskers bevegelser. ... -
Direct assessment of Kolmogorov's first refined similarity hypothesis
Lawson, John M; Bodenschatz, Eberhard; Knutsen, Anna Nina; Dawson, James; Worth, Nicholas (Journal article; Peer reviewed, 2019) -
The effect of hydrogen addition on the amplitude and harmonic response of azimuthal instabilities in a pressurized annular combustor
Indlekofer, Thomas; Ahn, Byeonguk; Kwah, Yi Hao; Wiseman, Samuel; Mazur, Marek; Dawson, James; Worth, Nicholas (Peer reviewed; Journal article, 2021)The present work introduces an annular combustion chamber operated at intermediate pressures. The combustor is operated with CH-H blends leading to a variety of azimuthal combustion instabilities. The influence of the ... -
The Effect of Hydrogen Enrichment on the Thermoacoustic Behaviour of Lean Premixed Flames
Æsøy, Eirik (Doctoral theses at NTNU;2022:23, Doctoral thesis, 2022)Gas turbines (GT) burning hydrogen can help deliver large-scale zero carbon power generation and facilitate rapid decarbonisation over the short to medium term. They can also play a crucial role in increasing the penetration ... -
The Effect of Hydrogen On Non-linear Flame Saturation
Æsøy, Eirik; Indlekofer, Thomas; Bothien, Mirko; Dawson, James (Peer reviewed; Journal article, 2023)We investigate the effect of hydrogen enrichment on the non-linear response and saturation of premixed methane/hydrogen flames submitted to acoustic forcing. The thermal power is kept fixed to preserve the nozzle velocity ... -
The Effect of Methane–Ammonia and Methane–Hydrogen Blends on Ignition and Light-Around in an Annular Combustor
Kwah, Yi Hao; Wiseman, Samuel Michael; Dawson, James (Journal article; Peer reviewed, 2023)The use of hydrogen and ammonia in gas turbines, either alone or blended with natural gas, poses various technical challenges for combustion systems, including ignition. Depending on the fuel composition, the laminar flame ... -
Experimental Measurement of Flame Describing Functions in an Azimuthally Forced Annular Combustor
Nygård, Håkon Tormodsen (Doctoral theses at NTNU;2021:178, Doctoral thesis, 2021)Thermoacoustic instabilities have become an increasingly relevant issue in the search for lower emissions in gas turbines, both for power production and transportation. Adoption of alternative fuels in land based gas ... -
Experimental Study of Damper Position on Instabilities in an Annular Combustor
Mazur, Marek; Nygård, Håkon Tormodsen; Dawson, James; Worth, Nicholas (Chapter, 2018)The present study experimentally investigates the effects of different circumferential damper configurations on the instabilities in an annular combustor. The combustor consists of multiple bluff body swirl stabilized ... -
Flame dynamics of azimuthal forced spinning and standing modes in an annular combustor
Nygård, Håkon Tormodsen; Mazur, Marek; Dawson, James; Worth, Nicholas (Journal article; Peer reviewed, 2018)Azimuthal forcing has been applied to flames in a laboratory scale annular combustor in order to accurately control the azimuthal mode of excitation. A new forcing configuration permitted not only the pressure amplitude, ...