54 results found
Jonker HJJ, Van Reeuwijk M, Sullivan PP, et al., 2012, Interfacial layers in clear and cloudy atmospheric boundary layers, 7th International Symposium on Turbulence, Heat and Mass Transfer, Publisher: International Centre for Heat and Mass Transfer
This paper reports on some recent advances in the understanding of the behaviour of atmosphericinterfacial layers. We focus on those interfaces where a turbulent layer is separated from a quiescentlayer by a relatively strong density gradient and study in particlar the entrainment rate, i.e. the rate withwhich the mixed layer penetrates into the quiescent layer by entraining fluid across the density interface.Making use of massively parallelized supercomputers, we conduct a large number of Direct NumericalSimulations (DNS) for a wide range of conditions and study the impact exerted on the entrainment rate bythe Reynolds number, the Prandtl/(Schmidt) number, and the strength of the density jump represented bythe Richardson number. We study two cases that are relevant for the atmosphere (/ocean), i.e. I] whereturbulence is generated by a surface buoyancy flux, and II] where turbulence is generated by shear (surfacemomentum flux). Of course with DNS one cannot simulate the high Reynolds numbers encountered in atmosphericcontexts, but present computer resources do allow us to faithfully simulate the classical laboratoryexperiments on these situations and even achieve Reynolds numbers more than ten times larger.
Lari KS, Van Reeuwijk M, Maksimovic C, 2012, Geometry effects in rough wall turbulent mass transfer, 7th International Symposium on Turbulence Heat and Mass Transfer (THMT), Publisher: BEGELL HOUSE, INC, Pages: 1709-1714
van Reeuwijk M, Sookhak Lari K, 2012, Asymptotic Solutions for turbulent mass transfer at high Schmidt number, PROC ROY SOC A
van Reeuwijk M, 2011, A mimetic mass, momentum and energy conserving discretization for the shallow water equations, COMPUTERS & FLUIDS, Vol: 46, Pages: 411-416, ISSN: 0045-7930
Sookhak Lari K, van Reeuwijk M, Maksimovic C, 2011, Combined bulk and wall reactions in turbulent pipe flow: decay coefficients and concentration profiles, J HYDROINF, Vol: 13, Pages: 324-333
van Reeuwijk M, Hunt GR, Jonker HJJ, 2011, Direct simulation of turbulent entrainment due to a plume impinging on a density interface
Sookhak Lari K, van Reeuwijk M, Maksimovic C, 2010, Simplified Numerical and Analytical Approach for Solutes in Turbulent Flow Reacting with Smooth Pipe Walls, J HYDR ENG (ASCE)
Mathias SA, Tsang C-F, Van Reeuwijk M, 2010, Investigation of hydromechanical processes during cyclic extraction recovery testing of a deformable rock fracture, INT J ROCK MECH MINING SCI
Sookhak Lari K, van Reeuwijk M, Maksimovic C, 2009, Is using a plane-channel geometry to model wall-demand in turbulent pipe flow justified?, Proc. Computing and Control in the Water Industry (CCWI)
Sookhak Lari K, Van Reeuwijk M, Maksimovic C, 2009, A study of wall demand in turbulent pipe flows, Sheffield, Proc. Computing and Control in the Water Industry (CCWI)
Sookhak Lari K, van Reeuwijk M, Maksimovic C, 2009, A study of wall demand in turbulent pipe flows, 10th International Conference on Computing and Control for the Water Industry Location: Sheffield, ENGLAND
van Reeuwijk M, Mathias SA, Simmons CT, et al., 2009, Insights from a pseudospectral approach to the Elder problem, WATER RESOUR RES, Vol: 45, W0441, ISSN: 0043-1397
The aim of this paper is to clarify and circumvent the issue of multiple steady state solutions in the Elder problem. A pseudospectral method is used to avoid numerical error associated with spatial discretization. The pseudospectral method is verified by comparison to an analytical solution at Rayleigh number, Ra = 0, and by reproducing the three stable steady state solutions that are known to exist at Ra = 400. A bifurcation diagram for 0 < Ra < 400 which is free of discretization error, confirms that multiple steady states are indeed an intrinsic characteristic of the Elder problem. The existence of multiple steady states makes the Ra = 400 Elder problem less suitable for benchmarking numerical models. To avoid the multiple steady states, we propose a benchmark at Ra = 60. The results for this Low Rayleigh Number Elder Problem are presented and compared to simulations with the commercial groundwater modeling package FEFLOW. Correspondence between the pseudospectral model and FEFLOW is excellent.
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2009, Leray-alpha simulations of wall-bounded turbulent flows, INT J HEAT FLUID FLOW
Mathias SA, van Reeuwijk M, 2009, Hydraulic fracture propagation with 3-D leak-off, TRANSPORT POROUS MED, Vol: In Press, ISSN: 0169-3913
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2008, Boundary layer scaling in Rayleigh-Benard convection, Proc. 5th European Thermal Sciences Conference
van Reeuwijk M, Mathias SA, Simmons CT, et al., 2008, Improving the worthiness of the Elder problem as a benchmark for buoyancy driven convection models, Virtual Conference on Climate Change and CO2 Storage, Publisher: Nature Precedings
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2008, Wind and boundary layers in Rayleigh-Benard convection. I. Analysis and modeling, PHYS REV E, Vol: 77
Verdoold J, van Reeuwijk M, Tummers MJ, et al., 2008, Spectral analysis of boundary layers in Rayleigh-Benard convection, PHYS REV E, Vol: 77
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2008, Wind and boundary layers in Rayleigh-Benard convection. II. Boundary layer character and scaling, PHYS REV E, Vol: 77
van Reeuwijk M, 2007, Direct simulation and regularization modeling of turbulent thermal convection, Phd. thesis
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2007, Applying the Leray-alpha model to unbounded Rayleigh-Benard convection, iTi Conference on Turbulence, Publisher: Springer, Pages: 197-200
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2006, Incompressibility of the Leray-alpha model for wall-bounded flows, PHYS FLUIDS, Vol: 18
van Reeuwijk M, Jonker HJJ, Hanjalic K, The role of the wind in unbounded Rayleigh-Benard convection, UK National Heat Transfer Conference
van Reeuwijk M, Jonker HJJ, Hanjalic K, 2005, Identification of the wind of Rayleigh-Benard convection, PHYS FLUIDS, Vol: 17
Using a symmetry-accounting ensemble-averaging method, we have identified the wind in unbounded Rayleigh–Bénard convection. This makes it possible to distinguish the wind from fluctuations and to identify dynamic features of each. We present some results from processing five independent three-dimensional direct numerical simulations of a =4 aspect-ratio domain with periodic side boundaries at Ra=107 and Pr=1. It is found that the wind boundary layer scales linearly very close to the wall and has a logarithmic region further away. Despite the still noticeable molecular effects, the identification of log scaling and significant velocity and temperature fluctuations well within the thermal boundary layer clearly indicate that the boundary layer cannot be classified as laminar.
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