| dc.date.accessioned | 2020-11-16T10:50:43Z | |
| dc.date.available | 2020-11-16T10:50:43Z | |
| dc.date.issued | 2020 | |
| dc.identifier.uri | http://hdl.handle.net/10852/81042 | |
| dc.description.abstract | Airflow above water waves represents a challenging problem, relevant both in air-sea interactions and for multiphase pipe flows. Understanding this interaction is important to accurately predict the exchange of heat, momentum and chemical components between the ocean and atmosphere, important for weather and climate models, and to obtain safe and reliable operation within the petroleum industry.
In the present thesis, optical measurement techniques are used to study the interaction between the phases of stratified gas-liquid flows. While the main focus is on air-water pipe flows, experiments are also performed in a combined wind-wave flume. Wave regimes ranging from regular ‘2D’ to chaotic ‘3D’ waves are analyzed.
3D waves are found to reverse the air-phase secondary flow structures compared with flow over a flat interface, impacting the momentum exchange between the phases. Within the 2D wave regime of air-water pipe flows, small scale wave breaking without air entrainment is found to be a frequent event. The effect of active wave breaking on the overlying airflow is analyzed both in the pipe flow setup and in a wind-wave flume. Results indicate that the geometrical properties of the waves dictate the airflow development, while the state of breaking has a secondary effect. | en_US |
| dc.language.iso | en | en_US |
| dc.relation.haspart | Paper I P. Vollestad, L. Angheluta and A. Jensen, ‘Experimental study of secondary flows above rough and flat interfaces in horizontal gas-liquid pipe flow’. In: International Journal of Multiphase Flow 125 (2020), 103235. DOI: 10.1016/j.ijmultiphaseflow.2020.103235. An author version is included in the thesis, the published version is available at: https://doi.org/10.1016/j.ijmultiphaseflow.2020.103235 | |
| dc.relation.haspart | Paper II P. Vollestad, A. A. Ayati, L. Angheluta, J. H. LaCasce and A. Jensen, ‘Experimental investigation of airflow above waves in a horizontal pipe’. In: International Journal of Multiphase Flow 110 (2019), pp. 37–49. DOI: 10.1016/j.ijmultiphaseflow.2018.08.008. An author version is included in the thesis, the published version is available at: https://doi.org/10.1016/j.ijmultiphaseflow.2018.08.008 | |
| dc.relation.haspart | Paper III P. Vollestad, A. A. Ayati and A. Jensen, ‘Microscale wave breaking in stratified air-water pipe flow’. In: Physics of Fluids 31 (2019), 032101. DOI: 10.1063/1.5082607. An author version is included in the thesis, the published version is available at: https://doi.org/10.1063/1.5082607 | |
| dc.relation.haspart | Paper IV P. Vollestad and A. Jensen, ‘Microbreaking and airflow separation in stratified air-water pipe flow - PIV setup and initial results’. In: Proceedings of the 13th International Symposium on Particle Image Velocimetry (2019), pp. 1435–1444. The paper is included in the thesis. | |
| dc.relation.haspart | Paper V P. Vollestad, A. A. Ayati and A. Jensen, ‘Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow’. In: Journal of Fluid Mechanics 878 (2019), pp. 796–819. DOI: 10.1017/jfm.2019.660. An author version is included in the thesis, the published version is available at: https://doi.org/10.1017/jfm.2019.660 | |
| dc.relation.haspart | Paper VI P. Vollestad and A. Jensen, ‘Modification of the airflow structure due to wave breaking on a submerged topography’. Under review. To be published. The paper is removed from the thesis in DUO awaiting publishing. | |
| dc.relation.haspart | Paper VII P. Vollestad and A. Jensen, ‘A note on PIV measurements of dilute air-sand pipe flow’. In preparation. To be published. The paper is removed from the thesis in DUO awaiting publishing. | |
| dc.relation.uri | https://doi.org/10.1016/j.ijmultiphaseflow.2020.103235 | |
| dc.relation.uri | https://doi.org/10.1016/j.ijmultiphaseflow.2018.08.008 | |
| dc.relation.uri | https://doi.org/10.1063/1.5082607 | |
| dc.relation.uri | https://doi.org/10.1017/jfm.2019.660 | |
| dc.title | Experimental investigations of two-phase flows. Dynamics of stratified and particle-laden flows in pipes and flumes | en_US |
| dc.type | Doctoral thesis | en_US |
| dc.creator.author | Vollestad, Petter | |
| dc.identifier.urn | URN:NBN:no-84129 | |
| dc.type.document | Doktoravhandling | en_US |
| dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/81042/1/PhD-Vollestad-DUO.pdf | |