Hostname: page-component-84b7d79bbc-7nlkj Total loading time: 0 Render date: 2024-07-26T07:47:59.386Z Has data issue: false hasContentIssue false
  • English
  • Français

Experimental investigation of intermittent airflow separation and microscale wave breaking in wavy two-phase pipe flow

Published online by Cambridge University Press:  18 September 2019

P. Vollestad Open the ORCID record for P. Vollestad [Opens in a new window] ,
A. A. Ayati  and
A. Jensen
P. Vollestad*
Affiliation:
Department of Mathematics, University of Oslo, 0316 Oslo, Norway
A. A. Ayati
Affiliation:
Department of Mathematics, University of Oslo, 0316 Oslo, Norway
A. Jensen
Affiliation:
Department of Mathematics, University of Oslo, 0316 Oslo, Norway
*
†Email address for correspondence: pettervo@math.uio.no
Get access Rights & Permissions [Opens in a new window]

Abstract

We perform an experimental analysis of co-current, stratified wavy pipe flow, with the aim of investigating the effect of small scale wave breaking (microscale breaking) on the airflow. Particle image velocimetry is applied simultaneously in the gas and liquid phases. Active wave breaking is identified by high levels of vorticity on the leeward side of individual waves, and the statistics of the airflow above breaking and non-breaking waves are extracted from the gas-phase velocity fields. Keeping the liquid superficial velocity constant ($U_{sl}=0.1~\text{m}~\text{s}^{-1}$), we consider two experimental cases of different gas flow rates. The lowest flow rate ($U_{sg}=1.85~\text{m}~\text{s}^{-1}$) is slightly higher than the onset of microscale breaking, while the higher flow rate ($U_{sg}=2.20~\text{m}~\text{s}^{-1}$) is within the regime where wave breaking is observed to be frequent, and the root-mean-square interface elevation $\unicode[STIX]{x1D702}_{rms}$ is independent of gas flow rate. Results show that for the lowest gas flow rate considered, active wave breaking has a stabilizing effect on the airflow above the waves, reducing the sheltered region on the leeward side of the wave and the turbulence above the wave crest compared with non-breaking waves at similar steepness. At the higher gas flow rate the effect of active wave breaking is found to be small, and the main geometrical properties of the waves are found to dominate the evolution of the separated flow region.

JFM classification

Waves/Free-surface Flows: Wave breaking
Type
JFM Papers
Information
Journal of Fluid Mechanics , Volume 878 , 10 November 2019 , pp. 796 - 819
Copyright
© 2019 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ayati, A. A., Kolaas, J., Jensen, A. & Johnson, G. W. 2014 A PIV investigation of stratified gas–liquid flow in a horizontal pipe. Intl J. Multiphase Flow 61, 129–143.Google Scholar
Ayati, A. A., Kolaas, J., Jensen, A. & Johnson, G. W. 2015 Combined simultaneous two-phase PIV and interface elevation measurements in stratified gas/liquid pipe flow. Intl J. Multiphase Flow 74, 45–58.Google Scholar
Ayati, A. A., Kolaas, J., Jensen, A. & Johnson, G. W. 2016 The effect of interfacial waves on the turbulence structure of stratified air/water pipe flow. Intl J. Multiphase Flow 78, 104–116.Google Scholar
Babanin, A. 2011 Breaking and Dissipation of Ocean Surface Waves. Cambridge University Press.Google Scholar
Banner, M. L. 1990 The influence of wave breaking on the surface pressure distribution in wind–wave interactions. J. Fluid Mech. 211, 463–495.Google Scholar
Banner, M. L. & Melville, W. K. 1976 On the separation of air flow over water waves. J. Fluid Mech. 77 (04), 825–842.Google Scholar
Banner, M. L. & Peirson, W. L. 1998 Tangential stress beneath wind-driven air–water interfaces. J. Fluid Mech. 364, 115–145.Google Scholar
Belcher, S. E. & Hunt, J. C. R. 1993 Turbulent shear flow over slowly moving waves. J. Fluid Mech. 251, 109–148.Google Scholar
Belcher, S. E. & Hunt, J. C. R. 1998 Turbulent flow over hills and waves. Annu. Rev. Fluid Mech. 30 (1), 507–538.Google Scholar
Birvalski, M. 2015 Experiments in Stratified Gas–Liquid Pipe Flow. TU Delft, Delft University of Technology.Google Scholar
Birvalski, M., Tummers, M. J., Delfos, R. & Henkes, R. A. W. M. 2015 Laminar-turbulent transition and wave-turbulence interaction in stratified horizontal two-phase pipe flow. J. Fluid Mech. 780, 439–456.Google Scholar
Birvalski, M., Tummers, M. J. & Henkes, R. A. W. M. 2016 Measurements of gravity and gravity-capillary waves in horizontal gas–liquid pipe flow using PIV in both phases. Intl J. Multiphase Flow 87, 102–113.Google Scholar
Buckley, M. P. & Veron, F. 2016 Structure of the airflow above surface waves. J. Phys. Oceanogr. 46 (5), 1377–1397.Google Scholar
Gent, P. R. & Taylor, P. A. 1977 A note on separation over short wind waves. Boundary-Layer Meteorol. 11 (1), 65–87.Google Scholar
Jessup, A. T., Zappa, C. J. & Yeh, H. 1997 Defining and quantifying microscale wave breaking with infrared imagery. J. Geophys. Res.: Oceans 102 (C10), 23145–23153.Google Scholar
Kawai, S. 1981 Visualization of airflow separation over wind–wave crests under moderate wind. Boundary-Layer Meteorol. 21 (1), 93–104.Google Scholar
Kawai, S. 1982 Structure of air flow separation over wind wave crests. Boundary-Layer Meteorol. 23 (4), 503–521.Google Scholar
Kihara, N., Hanazaki, H., Mizuya, T. & Ueda, H. 2007 Relationship between airflow at the critical height and momentum transfer to the traveling waves. Phys. Fluids 19 (1), 015102.Google Scholar
Kudryavtsev, V. N. & Makin, V. K. 2001 The impact of air-flow separation on the drag of the sea surface. Boundary-Layer Meteorol. 98 (1), 155–171.Google Scholar
Maat, N. & Makin, V. K. 1992 Numerical simulation of air flow over breaking waves. Boundary-Layer Meteorol. 60 (1–2), 77–93.Google Scholar
Phillips, O. M. 1958 The equilibrium range in the spectrum of wind-generated waves. J. Fluid Mech. 4 (4), 426–434.Google Scholar
Phillips, O. M. 1985 Spectral and statistical properties of the equilibrium range in wind-generated gravity waves. J. Fluid Mech. 156, 505–531.Google Scholar
Raffel, M., Willert, C. E., Scarano, F., Kähler, C. J., Wereley, S. T. & Kompenhans, J. 2018 Particle Image Velocimetry: a Practical Guide. Springer.Google Scholar
Reul, N., Branger, H. & Giovanangeli, J.-P. 2008 Air flow structure over short-gravity breaking water waves. Boundary-Layer Meteorol. 126 (3), 477–505.Google Scholar
Siddiqui, K. & Loewen, M. R. 2010 Phase-averaged flow properties beneath microscale breaking waves. Boundary-Layer Meteorol. 134 (3), 499–523.Google Scholar
Siddiqui, M. H. K. & Loewen, M. R. 2006 Detecting microscale breaking waves. Meas. Sci. Technol. 17 (4), 771–780.Google Scholar
Siddiqui, M. H. K. & Loewen, M. R. 2007 Characteristics of the wind drift layer and microscale breaking waves. J. Fluid Mech. 573, 417–456.Google Scholar
Smith, L., Kolaas, J., Jensen, A. & Sveen, K. 2018 Investigation of surface structures in two phase wavy pipe flow by utilizing x-ray tomography. Intl J. Multiphase Flow 107, 246–255.Google Scholar
Strand, O.1993 An experimental investigation of stratified two-phase flow in horizontal pipes. Dr. Scient. Thesis, University of Oslo. Oslo, Norway.Google Scholar
Sullivan, P. P., Banner, M. L., Morison, R. P. & Peirson, W. L. 2018a Impacts of wave age on turbulent flow and drag of steep waves. Procedia IUTAM 26, 174–183.Google Scholar
Sullivan, P. P., Banner, M. L., Morison, R. P. & Peirson, W. L. 2018b Turbulent flow over steep steady and unsteady waves under strong wind forcing. J. Phys. Oceanogr. 48 (1), 3–27.Google Scholar
Tian, Z., Perlin, M. & Choi, W. 2010 Observation of the occurrence of air flow separation over water waves. In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering, pp. 333–341. American Society of Mechanical Engineers.Google Scholar
Tulin, M. P. & Landrini, M. 2001 Breaking waves in the ocean and around ships. In 23rd Symposium on Naval Hydrodynamics, pp. 713–745. The National Academies Press.Google Scholar
Tzotzi, C. & Andritsos, N. 2013 Interfacial shear stress in wavy stratified gas–liquid flow in horizontal pipes. Intl J. Multiphase Flow 54, 43–54.Google Scholar
Ullmann, A. & Brauner, N. 2006 Closure relations for two-fluid models for two-phase stratified smooth and stratified wavy flows. Intl J. Multiphase Flow 32 (1), 82–105.Google Scholar
Veron, F., Saxena, G. & Misra, S. K. 2007 Measurements of the viscous tangential stress in the airflow above wind waves. Geophys. Res. Lett. 34 (19), L19603.Google Scholar
Vollestad, P., Ayati, A. A., Angheluta, L., LaCasce, J. H. & Jensen, A. 2019a Experimental investigation of airflow above waves in a horizontal pipe. Intl J. Multiphase Flow 110, 37–49.Google Scholar
Vollestad, P., Ayati, A. A. & Jensen, A. 2019b Microscale wave breaking in stratified air–water pipe flow. Phys. Fluids 31 (3), 032101.Google Scholar
Weissman, M. A. 1986 Observations and measurements of air flow over water waves. In Wave Dynamics and Radio Probing of the Ocean Surface, pp. 335–352. Springer.Google Scholar
Yang, Z., Deng, B.-Q. & Shen, L. 2018 Direct numerical simulation of wind turbulence over breaking waves. J. Fluid Mech. 850, 120–155.Google Scholar