Research Repository

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A novel wave-energy device with enhanced wave amplification and induction actuator (2019)
Conference Proceeding
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

The role of soluble surfactants in the linear stability of two-layer flow in a channel (2019)
Journal Article
Kalogirou, A., & Blyth, M. (2019). The role of soluble surfactants in the linear stability of two-layer flow in a channel. Journal of Fluid Mechanics, 873, 18-48

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

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. doi: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

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), doi: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

Modelling of Nonlinear Wave-Buoy Dynamics Using Constrained Variational Methods (2017)
Conference Proceeding
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. doi: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

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. doi: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

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, doi: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

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. doi: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

Mathematical and Numerical Modelling of Wave Impact on Wave-Energy Buoys (2016)
Conference Proceeding
Kalogirou, A., & Bokhove, O. (2016). Mathematical and Numerical Modelling of Wave Impact on Wave-Energy Buoys. doi: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

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. doi: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

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), doi: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

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. (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. doi: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