INPHYNI seminars: Valentin DUMAS (Photonique) / Klint ONGARI (Fluides)
- Science and society
Published on November 20, 2025
–
Updated on November 20, 2025
Dates
on the November 25, 2025
Café : 15h
Séminaire: 15h15
Séminaire: 15h15
Location
Salle des séminaires
Valentin Dumas - Quantum communication: from fiber network to satellite communications Klint Ongari - Studies on the circular hydraulic jump
Seminars of the Institut de Physique de Nice
Abstract:
Valentin Dumas - Quantum communication: from fiber network to satellite communications
This presentation explores recent advances that I made during my thesis in quantum communication, tracing the path from terrestrial fiber networks to emerging satellite-based quantum key distribution (QKD) links. We highlight a proof-of-principle experiment
demonstrating quantum key distribution over a 2.5-km free-space channel using polarization-entangled photon pairs. The talk will discuss the system design, entanglement distribution performance, and strategies for overcoming challenges such as turbulence, polarization stability and synchronization. By bridging laboratory protocols with real-world outdoor operation, this experiment underscores the feasibility of extending secure quantum communication to satellite platforms, paving the way for global quantum networks.
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Klint Ongari - Studies on the circular hydraulic jump
Structure formations in free surface flows remain a major source of complexity in hydrodynamics. One of the most well known and oldest problems is the hydraulic jump, where arise a sudden transition from a high speed, supercritical flow to a subcritical one, with a sudden jump of the fluid depth. It is possible to observe this phenomenon at very different scales: dam release flows, tidal bores on rivers, or in kitchen sinks when a vertical jet of liquid hits a horizontal surface. It’s surprising that such a simple and common phenomena, which hides intriguing and a rich dynamics [1, 2, 3], remain still not well understood.
In this seminar I’ll present my PhD work where we are investigating the formation of a circular hydraulic jump in a thin film layer. We are combining experimental measurements of the profile thickness using an optical confocal pen, with numerical simulations using Basilisk and combining everything with our theoretical model based on Inertial Lubrication Theory [4], in order to predict the thickness profile and the radius of the jump.
[1] J. B. Bélanger. Notes sur l’hydraulique. Ecole Royale des Ponts et Chaussees, Paris, France, session, 1842 :223, 1841.
[2] T. Bohr, V. Putkaradze, and S. Watanabe. Averaging theory for the structure of hydraulic jumps and separation in laminar free-surface flows. Physical review letters, 79(6) :1038, 1997.
[3] J. W. M. Bush, J. M. Aristoff, and A. E. Hosoi. An experimental investigation of the stability of the circular hydraulic jump. J. Fluid Mech., 558 :33–52, 2006.
[4] N. Rojas, M. Argentina, E. Cerda, and E. Tirapegui. Inertial lubrication theory. Physical review letters, 104(18): 187801, 2010.
Abstract:
Valentin Dumas - Quantum communication: from fiber network to satellite communications
This presentation explores recent advances that I made during my thesis in quantum communication, tracing the path from terrestrial fiber networks to emerging satellite-based quantum key distribution (QKD) links. We highlight a proof-of-principle experiment
demonstrating quantum key distribution over a 2.5-km free-space channel using polarization-entangled photon pairs. The talk will discuss the system design, entanglement distribution performance, and strategies for overcoming challenges such as turbulence, polarization stability and synchronization. By bridging laboratory protocols with real-world outdoor operation, this experiment underscores the feasibility of extending secure quantum communication to satellite platforms, paving the way for global quantum networks.
---------------------------
Klint Ongari - Studies on the circular hydraulic jump
Structure formations in free surface flows remain a major source of complexity in hydrodynamics. One of the most well known and oldest problems is the hydraulic jump, where arise a sudden transition from a high speed, supercritical flow to a subcritical one, with a sudden jump of the fluid depth. It is possible to observe this phenomenon at very different scales: dam release flows, tidal bores on rivers, or in kitchen sinks when a vertical jet of liquid hits a horizontal surface. It’s surprising that such a simple and common phenomena, which hides intriguing and a rich dynamics [1, 2, 3], remain still not well understood.
In this seminar I’ll present my PhD work where we are investigating the formation of a circular hydraulic jump in a thin film layer. We are combining experimental measurements of the profile thickness using an optical confocal pen, with numerical simulations using Basilisk and combining everything with our theoretical model based on Inertial Lubrication Theory [4], in order to predict the thickness profile and the radius of the jump.
[1] J. B. Bélanger. Notes sur l’hydraulique. Ecole Royale des Ponts et Chaussees, Paris, France, session, 1842 :223, 1841.
[2] T. Bohr, V. Putkaradze, and S. Watanabe. Averaging theory for the structure of hydraulic jumps and separation in laminar free-surface flows. Physical review letters, 79(6) :1038, 1997.
[3] J. W. M. Bush, J. M. Aristoff, and A. E. Hosoi. An experimental investigation of the stability of the circular hydraulic jump. J. Fluid Mech., 558 :33–52, 2006.
[4] N. Rojas, M. Argentina, E. Cerda, and E. Tirapegui. Inertial lubrication theory. Physical review letters, 104(18): 187801, 2010.