Research
Our research focuses on advancing the understanding and modelling of multiphase flows, addressing fundamental and applied research questions. To this end, tailored modeles and numerical methods are at the heart of our research and are essential for predicting the complex multiphase flows that we are investigating accurately and reliably. Advanced algorithms and parallel computation are integral to addressing the scale disparity and computational demands of these simulations using high-performance computing facilities. All the numerical methods we develop and use are custom-built to the flow phenomena or process we are investigating, enabling us to advance the knowledge on multiphase flows.
Cavitation bubble collapsing asymetrically close to a solid object, forming a fast liquid jet. Left: pressure contour; right: velocity field.
Cavitation
Cavitation, the formation, growth and collapse of gas or vapour bubbles in a liquid, is a highly dynamic phenomenon with significant implications across various applications. In transient pressure fields, understanding the onset of cavitation is crucial for predicting when and where cavitation will happen. Asymmetric cavitation collapse near walls introduces large localized pressures and shear stresses, leading to material erosion or deformation. These effects are leveraged in applications like surface cleaning and medical therapies, but require detailed modelling and simulation to optimize performance and mitigate undesired consequences. Our research addresses a wide range of questions associated with predicting the dynamics and impact of cavitation, with mitigating the negative impacts of cavitation and with leveraging the energy focusing driven by cavitation in engineering applications.
A liquid jet exiting a swirl atomizer, producing a large number of liquid droplets.
Dispersed multiphase flows
Dispersed multiphase flows, involving droplets, bubbles, or particles, play a critical role in numerous natural and industrial processes, such as spray dynamics and materials processing. We develop and apply advanced numerical methods to predict these flows across a wide spectrum, including polydisperse systems where the dispersed phase exhibits varying sizes and behaviours. Our work spans fully resolved simulations that capture intricate interfacial dynamics and interactions to efficient statistical models for large-scale, cost-effective predictions, enabling deeper insights and optimization of complex multiphase systems.
Slice through a water droplet (solid black circle) after it has interacted with a shock wave travelling at Mach 6. Top half: density gradient; bottom half: Mach number.
Multiphase flows under extreme conditions
Many multiphase flows exist under or drive extreme conditions, characterized for instance by large flow accelerations and high pressures. These conditions may cause rapid phase transition, induce interfacial instabilities, and are often associated with shock and rarefaction waves, drastically altering the flow and thermodynamics of the multiphase system. We develop custom-built physical models and numerical methods that allow us to predict and study nonlinear phenomena associated with this kind of flows, such as the interaction of bubbles and droplets with shock waves or the inertial confinement of gas-liquid systems.
An ellipsoidal particle in a supersonic flow of Mach 2. Shown in colour is the Mach number of the flow.
Particle dynamics
Particle dynamics, encompassing the motion of particles within a flow and their impact behaviour, is central to understanding and optimizing a variety of natural and industrial processes, such as sediment transport, powder handling, and additive manufacturing. We develop and utilize advanced numerical techniques to study particle-laden flows, capturing interactions between particles and the surrounding fluid as well as collisions and impacts between particles and surfaces. Our work ranges from detailed simulations that resolve individual particle dynamics to statistical and coarse-grained models that enable efficient prediction of large-scale systems, providing valuable insights into particle transport, dispersion, and impact phenomena.