Blar i Institutt for energi og prosessteknikk på tidsskrift "Journal of Fluid Mechanics"
Viser treff 1-20 av 38
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A comparative study of the velocity and vorticity structure in pipes and boundary layers at friction Reynolds numbers up to 10^4
(Journal article; Peer reviewed, 2019)This study presents findings from a first-of-its-kind measurement campaign that includes simultaneous measurements of the full velocity and vorticity vectors in both pipe and boundary layer flows under matched spatial ... -
Asynchronous and synchronous quenching of a globally unstable jet via axisymmetry breaking
(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 ... -
Degenerate perturbation theory in thermoacoustics: high-order sensitivities and exceptional points
(Peer reviewed; Journal article, 2020)In this study, we connect concepts that have been recently developed in thermoacoustics, specifically (i) high-order spectral perturbation theory, (ii) symmetry-induced degenerate thermoacoustic modes, (iii) intrinsic ... -
Designing vortices in pipe flow with topography-driven Langmuir circulation
(Peer reviewed; Journal article, 2021)We present direct numerical simulation of a mechanism for creating longitudinal vortices in pipe flow, compared with a model theory. By furnishing the pipe wall with a pattern of crossing waves, secondary flow in the form ... -
The effect of inlet turbulence on the quiescent core of turbulent channel flow
(Peer reviewed; Journal article, 2022)The impact of inlet turbulence on the structure of turbulent channel flow is investigated using particle image velocimetry. Streamwise–wall-normal plane measurements are performed in a channel, where different turbulence ... -
Effects of shear-thinning rheology on near-wall turbulent structures
(Peer reviewed; Journal article, 2021)Turbulent channel flow simulation of a shear-thinning fluid is considered – see Arosemena et al. (J. Fluid Mech., vol. 908, 2021, p. A43) – and compared with a Newtonian base case to reveal the effects of the shear-dependent ... -
Experimental study of the mutual interactions between waves and tailored turbulence
(Peer reviewed; Journal article, 2023)When surface waves interact with ambient turbulence, the two affect each other mutually. Turbulent eddies get redirected, intensified and periodically stretched and compressed, while the waves suffer directional scattering. ... -
Getting the ducks in a row
(Peer reviewed; Journal article, 2021)Vessels – in the widest sense – travelling on a water surface continuously do work the water surrounding it, causing energy to be radiated in the form of surface waves. The concomitant resistance force, the wave resistance, ... -
The inter-scale energy budget in a von Kármán mixing flow
(Peer reviewed; Journal article, 2020)A detailed assessment of the inter-scale energy budget of the turbulent flow in a von Kármán mixing tank has been performed based on two extensive experimental data sets. Measurements were performed at a Taylor microscale ... -
Langmuir-type vortices in wall-bounded flows driven by a criss-cross wavy wall topography
(Peer reviewed; Journal article, 2020)We investigate a mechanism to manipulate wall-bounded flows whereby wave-like undulations of the wall topography drives the creation of bespoke longitudinal vortices. A resonant interaction between the ambient vorticity ... -
Multiple resonances of a moving oscillating surface disturbance on a shear current
(Journal article; Peer reviewed, 2016) -
Observation of surface wave patterns modified by sub-surface shear currents
(Journal article; Peer reviewed, 2019)We report experimental observations of two canonical surface wave patterns – ship waves and ring waves – skewed by sub-surface shear, thus confirming effects predicted by recent theory. Observed ring waves on a still surface ... -
The response of an axisymmetric jet placed at various positions in a standing wave
(Peer reviewed; Journal article, 2021)The hydrodynamic response of an axisymmetric jet placed at various positions in a standing wave oriented normally to the jet is investigated. At the velocity and pressure nodes the axisymmetric (m=0) and first azimuthal ... -
Response of the temporal turbulent boundary layer to decaying free-stream turbulence
(Peer reviewed; Journal article, 2020)The turbulent boundary layer developing under a turbulence-laden free stream isnumerically investigated using the temporal boundary layer framework. This studyfocuses on the interaction between the ... -
Revisiting the reattachment regime: a closer look at tandem cylinder flow at Re=10000
(Peer reviewed; Journal article, 2022)Tandem cylinder flow comprises several different flow regimes. Within the reattachment regime, the development of the gap shear layers is of utmost importance to the flow, but has received little attention so far. Through ... -
Robust features of a turbulent boundary layer subjected to high-intensity free-stream turbulence
(Journal article; Peer reviewed, 2018)The influence of the large scale organisation of free-stream turbulence on a turbulent boundary layer is investigated experimentally in a wind tunnel through hot-wire measurements. An active grid is used to generate ... -
The role of Lagrangian drift in the geometry, kinematics and dynamics of surface waves
(Peer reviewed; Journal article, 2023)The role of the Lagrangian mean flow, or drift, in modulating the geometry, kinematics and dynamics of rotational and irrotational deep-water surface gravity waves is examined. A general theory for permanent progressive ... -
Saturation of flames to multiple inputs at one frequency
(Peer reviewed; Journal article, 2023)Existing experimental results show that swirling flames in annular combustors respond with a different gain to acoustic azimuthal modes rotating in either the clockwise or anti-clockwise direction. The ratio R of these two ... -
Scale-dependent particle clustering in transitional wake flow
(Peer reviewed; Journal article, 2022)Dispersion and mixing of inertial point particles in the unsteady and three-dimensional wake of a circular cylinder at Re=200 are investigated via one-way coupled simulations. The presence of streamwise-oriented vortical ... -
Sensitivity of the Rayleigh criterion in thermoacoustics
(Peer reviewed; Journal article, 2020)Thermoacoustic instabilities are one of the most challenging problems faced by gas turbine and rocket motor manufacturers. The key instability mechanism is described by the Rayleigh criterion. The Rayleigh criterion does ...