Multiphase Flows


  • Alejandro Sevilla
  • Javier Rodríguez
  • Carlos Martínez Bazán (Univ. de Jaén)
  • José Manuel Gordillo (Univ. de Sevilla)
  • Enrique Sanmiguel Rojas (Univ. de Jaén)
  • Rocío Bolaños (Univ. de Jaén)
  • Wilfried Coenen (University California San Diego)

Topics of interest

Turbulent Multiphase Flows

The dynamics of a population of bubbles inmersed into a turbulent flow is of interest for a number of applications, both in industry and natural sciences: gas-liquid chemical reactors, ocean-atmosphere interaction, underwater noise produced in the wake of a ship or aireation of rivers are just a few examples. Our research is focused on two topics:
- Air entrainment in turbulent spilling breakers.
- Turbulent breakup of bubbles.

  • J. Rodríguez-Rodríguez, C. Marugán-Cruz, A. Aliseda and J.C. Lasheras. Dynamics of large turbulent structures in a hydraulic jump. Journal of Fluid Mechanics, Submitted (2008)
  • A. Revuelta, J. Rodríguez-Rodríguez and C. Martínez-Bazán. Bubble breakup in a straining flow at finite Reynolds number. Journal of Fluid Mechanics, 551, 175-184 (2006)
  • J. Rodríguez-Rodríguez, J.M. Gordillo and C. Martínez-Bazán. Breakup time and morphology of drops and bubbles in a high-Reynolds number flow. Journal of Fluid Mechanics, 548, 69-86 (2006)
  • J. Rodríguez-Rodríguez, C. Martínez-Bazán and J.L. Montanés. A novel particle tracking and break-up detection algorithm: application to the turbulent break-up of bubbles. Measurement Science and Technology, 14, 1328-1340 (2003)
Plunging Waves

The flow downstream the stern of a ship exhibits a complex wave pattern that results in the entrainment of large amounts of air in the wake. The difference in height between the separated stream and the free surface level immediately after the stern induces a transversal velocity component to the separated water mass that deflects its otherwise streamwise velocity towards the centerline of the hull. As a result, two symmetrical waves are formed. The collision of these waves leads to a complex structure, known as rooster tail, that is responsible for an important fraction of the total amount of entrained air in the wake.It's possible to study the formation and the main features of these waves using a semi-submerged plate in a uniform stream. This wave originates a breaker that shares many features with two-dimensional deep-water breakers like those observed in the upper ocean. This is a consequence of the slender nature of the flow, as the streamwise velocity is much larger than the other two components.

The existence of different breaker configurations can be studied using this easy laboratory set up. Spilling breakers and plunging breakers can be studied separately in a steady flow which is convenient in the study of the mechanisms that lead to one or the other, and that are not fully understood, partly due to the lack of good-quality measurements.

The objective of this research line is to determine a criterion to predict which configuration will exhibit the above described waves. Furthermore, some insights into the physics of the breaker will allow us to predict, not only the breaker configuration, but also some important features of the jet originated at the wave crest in the case of plunging breakers. It is worth noticing that the ability to model the behavior of this flow constitutes a tool to predict the air exchange between the waves, either generated by a ship or not, and the ocean.

  • P. Martínez-Legazpi, J.Rodríguez-Rodríguez, Juan C. Lasheras, Corner waves downstream a partially submerged vertical plate, Proceedings 27th Symposium on Naval Hydrodynamics, Seoul, Korea, 2008.
  • P. Martínez-Legazpi, J.Rodríguez-Rodríguez, Juan C. Lasheras, Formation mechanism of corner waves downstream a partially submerged vertical plate, Proceedings 28th Symposium on Naval Hydrodynamics, Pasadena,CA, USA,  2010.