Browsing by Author "Mellado González, Juan Pedro"
Now showing items 1-20 of 51
-
A conceptual model of a shallow circulation induced by prescribed low-level radiative cooling
(2017-10-01)
Article
Open AccessA conceptual bulk model for a dry, convective boundary layer with prescribed horizontally homogeneous and heterogeneous low-level radiative cooling rates is developed. For horizontally homogeneous radiative cooling, the ... -
A refined statistical cloud closure using double-Gaussian probability density functions
(2013-10-08)
Article
Open AccessWe introduce a probability density function (PDF)-based scheme to parameterize cloud fraction, average liquid water and liquid water flux in large-scale models, that is developed from and tested against large-eddy simulations ... -
A study of the flow-field evolution and mixing in a planar turbulent jet using direct numerical simulation
(2002-01-10)
Article
Open AccessTurbulent plane jets are prototypical free shear flows of practical interest in propulsion, combustion and environmental flows. While considerable experimental research has been performed on planar jets, very few ... -
Analysis of external and global intermittency in the logarithmic layer of Ekman flow
(2016-10-25)
Article
Open AccessExistence of non-turbulent flow patches in the vicinity of the wall of a turbulent flow is known as global intermittency. Global intermittency challenges the conventional statistics approach when describing turbulence ... -
Buoyancy reversal in cloud-top mixing layers
(2009-04-28)
Article
Open AccessA theoretical and numerical small-scale study of the evaporative cooling phenomenon that might appear in the stratocumulus-topped boundary layers is presented. An ideal configuration of a cloud-top mixing layer is ... -
Characterization of wind-shear effects on entrainment in a convective boundary layer
(2019-01-10)
Article
Open AccessDirect numerical simulations are used to characterize wind-shear effects on entrainment in a barotropic convective boundary layer (CBL) that grows into a linearly stratified atmosphere. We consider weakly to strongly ... -
Cloud droplets in a bulk formulation and its application for the buoyancy reversal instability
(2014-07-28)
Article
Open AccessMixing processes at the boundary of clouds often include typical length-scales of several metres. Such length-scales are too large for current Lagrangian models but they are also poorly resolved by typical Eulerian-based ... -
Cloud-aerosol-turbulence interactions: Science priorities and concepts for a large-scale laboratory facility
(2020-07-17)
Article
Open AccessClouds and aerosols, ubiquitously embedded in turbulent flows, are central to the prediction of weather and climate. The purpose of the workshop described here was to explore scientific questions and set priorities for a ... -
Cloud-top entrainment in stratocumulus clouds
(2017-01-01)
Article
Restricted access - publisher's policyCloud entrainment, the mixing between cloudy and clear air at the boundary of clouds, constitutes one paradigm for the relevance of small scales in the Earth system: By regulating cloud lifetimes, meter- and submeter-scale ... -
Competing effects of wind shear and droplet sedimentation at stratocumulus tops
(2019-06-25)
Article
Open AccessThe joint effect of droplet sedimentation and wind shear on cloud top entrainment in stratocumulus is investigated with direct numerical simulations. Although it is well understood that droplet sedimentation weakens ... -
Controlling entrainment in the smoke cloud using level set-based front tracking
(2015-01-13)
Article
Open AccessAlthough large-eddy simulation (LES) has been shown to produce a reasonable representation of the turbulent circulations within the stratocumulus-topped boundary layer, it has difficulties to accurately predict ... -
Direct Numerical Simulation of evaporative cooling at the lateral boundary of shallow cumulus clouds
(2013-07-23)
Article
Open AccessThis study investigates the dynamics of the subsiding shell at the lateral boundary of cumulus clouds, focusing on the role of evaporative cooling. Since the size of this shell is well below what large-eddy simulations can ... -
Direct numerical simulation of free convection over a heated plate
(2012-12-10)
Article
Open AccessDirect numerical simulations of free convection over a smooth, heated plate are used to investigate unbounded, unsteady turbulent convection. Four different boundary conditions are considered: free-slip or no-slip walls, ... -
Direct Numerical Simulations of a smoke cloud-top mixing layer as a model for stratocumuli
(2013-08-05)
Article
Open AccessA radiatively driven cloud-top mixing layer is investigated using direct numerical simulations. This configuration mimics the mixing process across the inversion that bounds the stratocumulus-topped boundary layer. The ... -
DNS and LES for simulating stratocumulus: Better together
(2018-07-05)
Article
Open AccessWe argue that combining direct numerical simulation (DNS) with large-eddy simulation (LES) and field studies could accelerate current lines of stratocumulus research. LES allows for a faster and more holistic study of ... -
Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments
(European Geosciences Union (EGU), 2021-01-14)
Article
Open AccessWe employed direct numerical simulations to esti- mate the error on chemical calculation in simulations with re- gional chemical-transport models induced by neglecting sub- grid chemical segregation due to inefficient ... -
Estimating turbulence kinetic energy dissipation rate in numerically simulated stratocumulus cloud-top mixing layers
(2019-05-01)
Article
Open AccessIn this work, direct numerical simulation (DNS) of the stratocumulus cloud-top mixing layer is used to test various approaches to estimate the turbulence kinetic energy (TKE) dissipation rate « from one-dimensional (1D) ... -
Evaporative cooling amplification of the entrainment velocity in radiatively driven stratocumulus
(2015-09-15)
Article
Open AccessEvaporative cooling monotonically increases as the thermodynamical properties of the inversion allow for more evaporation in shear-free radiatively driven stratocumulus. However, the entrainment velocity can deviate from ... -
Factorization of the Fourier transform of the pressure-Poisson equation using finite differences in colocated grids
(Wiley-VCH, 2012-02-29)
Article
Open AccessThe zero-divergence constraint on the velocity field in the numerical simulation of incompressible flows can be reduced, in certain cases, to a set of one-dimensional linear difference equations for the pressure. These ... -
Fractal reconstruction of sub-grid scales for large eddy simulation
(springer-Verlag, 2019-05-28)
Article
Open AccessIn this work, the reconstruction of sub-grid scales in large eddy simulation (LES) of turbulent flows in stratocumulus clouds is addressed. The approach is based on the fractality assumption of turbulent velocity field. ...
