Aortic valve neocuspidization and bioprosthetic valves: Evaluating turbulence haemodynamics

Aortic valve disease is often treated with bioprosthetic valves. An alternative treatment is aortic valve neocuspidization which is a relatively new reparative procedure whereby the three aortic cusps are replaced with patient pericardium or bovine tissues. Recent research indicates that aortic blood flow is disturbed, and turbulence effects...

Drivers for mass and momentum exchange between the main channel and river bank lateral cavities

Large-Eddy Simulations (LES) are used to investigate the governing processes involved in mass and momentum transfer between the flow in the main channel and symmetrically-distributed lateral bank cavities. In-cavity free-surface velocities, based on laboratory measurements made in an open channel, are used to validate the numerical results. A...

Unravelling Turbulent Emulsions with lattice-Boltzmann simulations

The mixing of two immiscible fluids, often under turbulent conditions, can lead to the formation of an emulsion, where droplets of one fluid are embedded in another fluid. The occurrence of emulsions is commonplace across industries, ranging from the oil industry to food processing and biotechnology. Why emulsions serve diverse applications, in...

Assessment of numerical methods for fully resolved simulations of particle-laden turbulent flows

During the last decade, many approaches for resolved-particle simulation (RPS) have been developed for numerical studies of finite-size particle-laden turbulent flows. In this paper, three RPS approaches are compared for a particle-laden decaying turbulence case. These methods are, the Volume-of-Fluid Lagrangian method, based on the viscosity...

Towards Adaptive Grids for Atmospheric Boundary-Layer Simulations

We present a proof-of-concept for the adaptive mesh refinement method applied to atmospheric boundary-layer simulations. Such a method may form an attractive alternative to static grids for studies on atmospheric flows that have a high degree of scale separation in space and/or time. Examples include the diurnal cycle and a convective...

Turbulence and turbulent heat transfer at supercritical pressure

Marangoni driven turbulence in high energy surface melting processes

Experimental observations of high-energy surface melting processes, such as laser welding, have revealed unsteady, often violent, motion of the free surface of the melt pool. Surprisingly, no similar observations have been reported in numerical simulation studies of such flows. Moreover, the published simulation results fail to predict the...

Large-scale turbulence structures in shallow separating flows

The Ph.D. thesis “Large-scale turbulence structures in shallow separating flows” by Harmen Talstra is the result of a Ph.D. research project on large-scale shallow-flow turbulence, which has been performed in the Environmental Fluid Mechanics Laboratory at Delft University of Technology. The dynamics of quasi two-dimensional turbulence...