ANNA KALOGIROU's Outputs (23)

A study of extreme water waves using a hierarchy of models based on potential-flow theory (2024)
Journal Article
Choi, J., Kalogirou, A., Lu, Y., Bokhove, O., & Kelmanson, M. (2024). A study of extreme water waves using a hierarchy of models based on potential-flow theory. Water Waves, 6, 225-277. https://doi.org/10.1007/s42286-024-00084-4

The formation of extreme waves arising from the interaction of three line-solitons with equal far-field amplitudes is examined through a hierarchy of water-wave models. The Kadomtsev–Petviashvili equation (KPE) is first used to prove analytically tha... Read More about A study of extreme water waves using a hierarchy of models based on potential-flow theory.

Nonlinear dynamics of unstably stratified two-layer shear flow in a horizontal channel (2023)
Journal Article
Kalogirou, A., & Blyth, M. (2023). Nonlinear dynamics of unstably stratified two-layer shear flow in a horizontal channel. Journal of Fluid Mechanics, 955, Article A32. https://doi.org/10.1017/jfm.2022.1070

The Rayleigh-Taylor instability at the interface of two sheared fluid layers in a horizontal channel is investigated in the absence of inertia. The dynamics of the flow is described by a nonlinear lubrication equation which is solved numerically for... Read More about Nonlinear dynamics of unstably stratified two-layer shear flow in a horizontal channel.

Numerical Experiments on Extreme Waves Through Oblique–Soliton Interactions (2022)
Journal Article
Choi, J., Bokhove, O., Kalogirou, A., & Kelmanson, M. A. (2022). Numerical Experiments on Extreme Waves Through Oblique–Soliton Interactions. Water Waves, 4(2), 139–179. https://doi.org/10.1007/s42286-022-00059-3

Extreme water-wave motion is investigated analytically and numerically by considering two-soliton and three-soliton interactions on a horizontal plane. We successfully determine numerically that soliton solutions of the unidirectional Kadomtsev–Petvi... Read More about Numerical Experiments on Extreme Waves Through Oblique–Soliton Interactions.

Instabilities at a sheared interface over a liquid laden with soluble surfactant (2021)
Journal Article
Kalogirou, A., & Blyth, M. G. (2021). Instabilities at a sheared interface over a liquid laden with soluble surfactant. Journal of Engineering Mathematics, 129, Article 3. https://doi.org/10.1007/s10665-021-10140-4

The linear stability of a semi-infinite fluid undergoing a shearing motion over a fluid layer that is laden with soluble surfactant and that is bounded below by a plane wall is investigated under conditions of Stokes flow. While it is known that this... Read More about Instabilities at a sheared interface over a liquid laden with soluble surfactant.

Nonlinear dynamics of two-layer channel flow with soluble surfactant below or above the critical micelle concentration (2020)
Journal Article
Kalogirou, A., & Blyth, M. (2020). Nonlinear dynamics of two-layer channel flow with soluble surfactant below or above the critical micelle concentration. Journal of Fluid Mechanics, 900, Article A7. https://doi.org/10.1017/jfm.2020.480

© 2020 Cambridge University Press. All rights reserved. The nonlinear stability of an inertialess two-layer surfactant-laden Couette flow is considered. The two fluids are immiscible and have different thicknesses, viscosities and densities. One of t... Read More about Nonlinear dynamics of two-layer channel flow with soluble surfactant below or above the critical micelle concentration.

A novel wave-energy device with enhanced wave amplification and induction actuator (2020)
Journal Article
Bokhove, O., Kalogirou, A., Henry, D., & Thomas, G. P. (2020). A novel wave-energy device with enhanced wave amplification and induction actuator. International Marine Energy Journal, 3(1), 37-44. https://doi.org/10.36688/imej.3.37-44

© 2020, European Wave and Tidal Energy Conference. All rights reserved. A novel wave-energy device is presented. Both a preliminary proof-of-principle of a working, scaled laboratory version of the energy device is shown as well as the derivation and... Read More about A novel wave-energy device with enhanced wave amplification and induction actuator.

From bore-soliton-splash to a new wave-to-wire wave-energy model (2019)
Journal Article
Bokhove, O., Kalogirou, A., & Zweers, W. (2019). From bore-soliton-splash to a new wave-to-wire wave-energy model. Water Waves, 1(2), 217-218. https://doi.org/10.1007/s42286-019-00022-9

We explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound ru... Read More about From bore-soliton-splash to a new wave-to-wire wave-energy model.

Asymptotic modelling and direct numerical simulations of multilayer pressure-driven flows (2019)
Journal Article
Kalogirou, A., Cimpeanu, R., & Blyth, M. (2020). Asymptotic modelling and direct numerical simulations of multilayer pressure-driven flows. European Journal of Mechanics - B/Fluids, 80, 195-205. https://doi.org/10.1016/j.euromechflu.2019.10.011

The nonlinear dynamics of two immiscible superposed viscous fluid layers in a channel is examined using asymptotic modelling and direct numerical simulations (DNS). The flow is driven by an imposed axial pressure gradient. Working on the assumption t... Read More about Asymptotic modelling and direct numerical simulations of multilayer pressure-driven flows.

A novel wave-energy device with enhanced wave amplification and induction actuator (2019)
Presentation / Conference Contribution
Bokhove, O., Kalogirou, A., Henry, D., & Thomas, G. P. (2019). A novel wave-energy device with enhanced wave amplification and induction actuator

A novel wave-energy device will be presented. Both a preliminary proof-of-principle of a working, scaled laboratory version of the energy device will be shown as well as the derivation and analysis of a comprehensive mathematical and numerical model... Read More about A novel wave-energy device with enhanced wave amplification and induction actuator.

The role of soluble surfactants in the linear stability of two-layer flow in a channel (2019)
Journal Article
Kalogirou, A., & Blyth, M. G. (2019). The role of soluble surfactants in the linear stability of two-layer flow in a channel. Journal of Fluid Mechanics, 873, 18-48. https://doi.org/10.1017/jfm.2019.392

The linear stability of Couette-Poiseuille flow of two superposed fluid layers in a horizontal channel is considered. The lower fluid layer is populated with surfactants that appear either in the form of monomers or micelles and can also get adsorbed... Read More about The role of soluble surfactants in the linear stability of two-layer flow in a channel.

Nonlinear dynamics of a dispersive anisotropic Kuramoto–Sivashinsky equation in two space dimensions (2018)
Journal Article
Tomlin, R. J., Kalogirou, A., & Papageorgiou, D. T. (2018). Nonlinear dynamics of a dispersive anisotropic Kuramoto–Sivashinsky equation in two space dimensions. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 474(2211), 20170687. https://doi.org/10.1098/rspa.2017.0687

A Kuramoto–Sivashinsky equation in two space dimensions arising in thin film flows is considered on doubly periodic domains. In the absence of dispersive effects, this anisotropic equation admits chaotic solutions for sufficiently large length scales... Read More about Nonlinear dynamics of a dispersive anisotropic Kuramoto–Sivashinsky equation in two space dimensions.

Instability of two-layer film flows due to the interacting effects of surfactants, inertia, and gravity (2018)
Journal Article
Kalogirou, A. (2018). Instability of two-layer film flows due to the interacting effects of surfactants, inertia, and gravity. Physics of Fluids, 30(3), Article 030707. https://doi.org/10.1063/1.5010896

We consider a two-fluid shear flow where the interface between the two fluids is coated with an insoluble surfactant. An asymptotic model is derived in the thin-layer approximation, consisting of a set of nonlinear partial differential equations desc... Read More about Instability of two-layer film flows due to the interacting effects of surfactants, inertia, and gravity.

Modelling of nonlinear wave-buoy dynamics using constrained variational methods (2017)
Presentation / Conference Contribution
Kalogirou, A., Bokhove, O., & Ham, D. (2017). Modelling of nonlinear wave-buoy dynamics using constrained variational methods. In ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering (1-10). https://doi.org/10.1115/OMAE2017-61966

We consider a comprehensive mathematical and numerical strategy to couple water-wave motion with rigid ship dynamics using variational principles. We present a methodology that applies to three-dimensional potential flow water waves and ship dynamics... Read More about Modelling of nonlinear wave-buoy dynamics using constrained variational methods.

Variational modelling of extreme waves through oblique interaction of solitary waves: application to Mach reflection (2017)
Journal Article
Gidel, F., Bokhove, O., & Kalogirou, A. (2017). Variational modelling of extreme waves through oblique interaction of solitary waves: application to Mach reflection. Nonlinear Processes in Geophysics, 24(1), 43-60. https://doi.org/10.5194/npg-24-43-2017

In this work, we model extreme waves that occur due to Mach reflection through the intersection of two obliquely incident solitary waves. For a given range of incident angles and amplitudes, the Mach stem wave grows linearly in length and amplitude,... Read More about Variational modelling of extreme waves through oblique interaction of solitary waves: application to Mach reflection.

Capturing nonlinear dynamics of two-fluid Couette flows with asymptotic models (2016)
Journal Article
Kalogirou, A., Cîmpeanu, R., Keaveny, E., & Papageorgiou, D. (2016). Capturing nonlinear dynamics of two-fluid Couette flows with asymptotic models. Journal of Fluid Mechanics, 806, R1. https://doi.org/10.1017/jfm.2016.612

The nonlinear stability of two-fluid Couette flows is studied using a novel evolution equation whose dynamics is validated by direct numerical simulation (DNS). The evolution equation incorporates inertial effects at arbitrary Reynolds numbers throug... Read More about Capturing nonlinear dynamics of two-fluid Couette flows with asymptotic models.

Nonlinear dynamics of surfactant-laden two-fluid Couette flows in the presence of inertia (2016)
Journal Article
Kalogirou, A., & Papageorgiou, D. T. (2016). Nonlinear dynamics of surfactant-laden two-fluid Couette flows in the presence of inertia. Journal of Fluid Mechanics, 802, 5-36. https://doi.org/10.1017/jfm.2016.429

The nonlinear stability of immiscible two-fluid Couette flows in the presence of inertia is considered. The interface between the two viscous fluids can support insoluble surfactants and the interplay between the underlying hydrodynamic instabilities... Read More about Nonlinear dynamics of surfactant-laden two-fluid Couette flows in the presence of inertia.

Mathematical and Numerical Modelling of Wave Impact on Wave-Energy Buoys (2016)
Presentation / Conference Contribution
Kalogirou, A., & Bokhove, O. (2016). Mathematical and Numerical Modelling of Wave Impact on Wave-Energy Buoys. . https://doi.org/10.1115/omae2016-54937

We report on the mathematical and numerical modelling of amplified rogue waves driving a wave-energy device in a contraction. This wave-energy device consists of a floating buoy attached to an AC-induction motor and constrained to move upward only in... Read More about Mathematical and Numerical Modelling of Wave Impact on Wave-Energy Buoys.

Variational finite element methods for waves in a Hele-Shaw tank (2016)
Journal Article
Kalogirou, A., Moulopoulou, E. E., & Bokhove, O. (2016). Variational finite element methods for waves in a Hele-Shaw tank. Applied Mathematical Modelling, 40(17-18), 7493-7503. https://doi.org/10.1016/j.apm.2016.02.036

The damped motion of driven water waves in a Hele-Shaw tank is investigated variationally and numerically. The equations governing the hydrodynamics of the problem are derived from a variational principle for shallow water. The variational principle... Read More about Variational finite element methods for waves in a Hele-Shaw tank.

Variational water wave modelling: from continuum to experiment (2016)
Book Chapter
Bokhove, O., & Kalogirou, A. (2016). Variational water wave modelling: from continuum to experiment. In Lectures on the Theory of Water Waves (226-260). Cambridge University Press. https://doi.org/10.1017/CBO9781316411155.012

© Cambridge University Press 2016. Variational methods are investigated asymptotically and numerically to model water waves in tanks with wave generators. As a validation, our modelling results using (dis)continuous Galerkin finite element methods wi... Read More about Variational water wave modelling: from continuum to experiment.

An in-depth numerical study of the two-dimensional Kuramoto–Sivashinsky equation (2015)
Journal Article
Kalogirou, A., Keaveny, E. E., & Papageorgiou, D. T. (2015). An in-depth numerical study of the two-dimensional Kuramoto–Sivashinsky equation. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 471(2179), Article 20140932. https://doi.org/10.1098/rspa.2014.0932

The Kuramoto–Sivashinsky equation in one spatial dimension (1D KSE) is one of the most well-known and well-studied partial differential equations. It exhibits spatio-temporal chaos that emerges through various bifurcations as the domain length increa... Read More about An in-depth numerical study of the two-dimensional Kuramoto–Sivashinsky equation.

Linearly implicit schemes for multi-dimensional Kuramoto–Sivashinsky type equations arising in falling film flows (2015)
Journal Article
Akrivis, G., Kalogirou, A., Papageorgiou, D. T., & Smyrlis, Y.-S. (2016). Linearly implicit schemes for multi-dimensional Kuramoto–Sivashinsky type equations arising in falling film flows. IMA Journal of Numerical Analysis, 36(1), 317–336. https://doi.org/10.1093/imanum/drv011

This study introduces, analyses and implements space-time discretizations of two-dimensional active dissipative partial differential equations such as the Topper–Kawahara equation; this is the two-dimensional extension of the dispersively modified Ku... Read More about Linearly implicit schemes for multi-dimensional Kuramoto–Sivashinsky type equations arising in falling film flows.

Surfactant destabilization and non-linear phenomena in two-fluid shear flows at small Reynolds numbers (2012)
Presentation / Conference Contribution
Kalogirou, A., Papageorgiou, D. T., & Smyrlis, Y.-. S. (2011, July). Surfactant destabilization and non-linear phenomena in two-fluid shear flows at small Reynolds numbers. Presented at The IMA Conference on Nonlinearity and Coherent Structures, Reading, UK

The flow of two superposed fluids in a channel in the presence of an insoluble surfactant is studied. Asymptotic analysis when one of the layers is thin yields a system of coupled weakly non-linear evolution equations for the film thickness and the l... Read More about Surfactant destabilization and non-linear phenomena in two-fluid shear flows at small Reynolds numbers.

Incompressible Poiseuille flows of Newtonian liquids with a pressure-dependent viscosity (2011)
Journal Article
Kalogirou, A., Poyiadji, S., & Georgiou, G. C. (2011). Incompressible Poiseuille flows of Newtonian liquids with a pressure-dependent viscosity. Journal of Non-Newtonian Fluid Mechanics, 166(7-8), 413-419. https://doi.org/10.1016/j.jnnfm.2011.01.006

The pressure-dependence of the viscosity becomes important in flows where high pressures are encountered. Applications include many polymer processing applications, microfluidics, fluid film lubrication, as well as simulations of geophysical flows. U... Read More about Incompressible Poiseuille flows of Newtonian liquids with a pressure-dependent viscosity.