Browsing by Subject "Large eddy simulation"

Article

Coherent structures in oscillating turbulent boundary layers over a fixed rippled bed

Grigoriadis, D. G. E.; Balaras, E.; Dimas, A. A. (2013)

Coherent structures generated by oscillating turbulent boundary layers with or without a unidirectional current over a fixed, rippled bed are presented. The effect of ripple height and current intensity on the characteristics ...

Conference Object

Computational fluid dynamics (CFD) Simulations of aerosol deposition in the lungs

Koullapis, P. G.; Kassinos, Stavros C.; Lin, C.-L. (TSFP-9, 2015)

In the current study, Large Eddy Simulations (LES) are used to investigate the transport and deposition of inhaled aerosol particles (dp = 0.1, 0.5, 1, 2.5, 5, 10 μm) in a realistic geometry of the human airways under ...

Article

Direct numerical simulation of particle laden flow in a human airway bifurcation model

Stylianou, F. S.; Sznitman, J.; Kassinos, Stavros C. (2016)

During the delivery of inhaled medicines, and depending on the size distribution of the particles in the formulation, airway bifurcations are areas of preferential deposition. Previous studies of laminar flow through airway ...

Conference Object

The effect of flow rate, head position, and inhaler orientation on the airflow and particle deposition in an mri-based mouth-throat geometry

Stylianou, F. S.; Angeli, S.; Kassinos, Stavros C.; Svensson, M. (International Symposium on Turbulence and Shear Flow Phenomena, TSFP10, 2017)

The mouth-throat plays a key role in the administration of inhaled medicines. It is an area of intense filtration, where an unacceptably high fraction of the released drug dose is deposited and thus wasted. Due to the ...

Conference Object

Effect of turbulent pulsating flow around a near-wall submerged cylinder on the potential motion of bed and suspended loads

Fonias, E. N.; Grigoriadis, D. G. E. (International Society of Offshore and Polar Engineers, 2016)

In the present work, the pulsating flow around a submerged cylinder close to the impermeable seabed is examined by means of Large Eddy Simulations (LES). A Reynolds number equal to Re = 5000 is considered, based on the ...

Article

Efficient treatment of complex geometries for large eddy simulations of turbulent flows

Grigoriadis, D. G. E.; Bartzis, J. G.; Goulas, A. (2004)

Incompressible turbulent flow over a backward facing step at Reh=5100 is investigated by large eddy simulations (LES). The ratio of the oncoming boundary layer thickness δ to the step height h was set to 1.2. Additionally ...

Conference Object

Fully turbulent flow in a physiologically realistic human airway bifurcation

Stylianou, F. S.; Kassinos, Stavros C. (TSFP-9, 2015)

Recent computational studies have shown that the airflow in the upper human airways is turbulent during much of the respiratory cycle. A feature of respiratory airflow that poses a challenge to computations based on ...

Article

In silico assessment of mouth-throat effects on regional deposition in the upper tracheobronchial airways

Koullapis, P. G.; Nicolaou, L.; Kassinos, Stavros C. (2018)

Regional deposition of inhaled medicines is a valuable metric of effectiveness in drug delivery applications to the lung. In silico methods are now emerging as a valuable tool for the detailed description of localized ...

Article

Lagrangian particle dispersion in turbulent flow over a wall mounted obstacle

Grigoriadis, D. G. E.; Kassinos, Stavros C. (2009)

Large-eddy simulations (LES) of particle-laden turbulent flows are presented in order to investigate the effects of particle response time on the dispersion patterns of a space developing flow with an obstruction, where ...

Article

Large Eddy Simulation of near-bed pipelines in oscillatory flow

Fonias, E. N.; Grigoriadis, D. G. E. (2018)

A series of unsteady, three-dimensional numerical simulations of the incompressible, oscillatory flow around a near-bed pipeline is presented. A flow at Reynolds number equal to Reαo=20,000 with respect to the oscillatory ...

Conference Object

Large eddy simulation of sediment transport for the pulsating flow past a cylinder over a horizontal bed

Fonias, E. N.; Grigoriadis, D. G. E. (International Society of Offshore and Polar Engineers, 2015)

In the present work, the suspended, pulsating incompressible flow past a submerged cylinder was examined by means of Large Eddy Simulations (LES). A layer of sandy inertial particles was allowed to move between the cylinder ...

Article

Large eddy simulation of thermocline flow phenomena and mixing during discharging of an initially homogeneous or stratified storage tank

Kaloudis, E.; Grigoriadis, D. G. E.; Papanicolaou, E.; Panidis, T. (2014)

This study investigates numerically the flow phenomena developing in the discharging process of a rectangular water tank used for thermal energy storage and how these affect the thermal mixing and the associated energy ...

Article

Large eddy simulations of turbulent mixed convection in the charging of a rectangular thermal storage tank

Kaloudis, E.; Grigoriadis, D. G. E.; Papanicolaou, E.; Panidis, T. (2013)

The Large Eddy Simulation (LES) approach is used to investigate numerically the mixed convection problem arising during the charging process of a rectangular water tank used for thermal energy storage. Two different charging ...

Article

Large-eddy simulation of wave turbulent boundary layer over rippled bed

Grigoriadis, D. G. E.; Dimas, A. A.; Balaras, E. (2012)

Large-eddy simulation (LES) of turbulent boundary layer induced by external oscillatory flow without or with a unidirectional component over rippled bottom is presented. These flows represent prototype turbulent flows of ...

Article

Large-eddy simulations of the turbulent Hartmann flow close to the transitional regime

Sarris, I. E.; Kassinos, Stavros C.; Carati, D. (2007)

A series of large-eddy simulations (LES) of turbulent and transitional channel flows of a conductive fluid under the effect of a uniform magnetic field applied in the wall-normal direction, usually referred to as Hartmann ...

Conference Object

Numerical modeling of turbulent airflow and particle deposition in a bifurcating airway model

Radhakrishnan, H.; Kassinos, Stavros C. (Affiliation: UCY-CompSci Computational Sciences Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, CyprusCorrespondence Address: Radhakrishnan, H.UCY-CompSci Computational Sciences Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus, 2009)

Understanding transport and deposition of inhaled particles in the human airways plays a crucial role in the targeted therapy of pulmonary diseases, and the administration of inhaled medicines. Numerous researchers have ...

Article

Particle deposition in a realistic geometry of the human conducting airways: Effects of inlet velocity profile, inhalation flowrate and electrostatic charge

Koullapis, P. G.; Kassinos, Stavros C.; Bivolarova, M. P.; Melikov, A. K. (2016)

Understanding the multitude of factors that control pulmonary deposition is important in assessing the therapeutic or toxic effects of inhaled particles. The use of increasingly sophisticated in silico models has improved ...