Simulation and numerical investigations of the kinetics of atmospheric aerosol droplets in the wake behind a flat plate

2009 ◽  
Vol 82 (2) ◽  
pp. 327-337 ◽  
Author(s):  
A. G. Zdor
2016 ◽  
Vol 26 (7) ◽  
pp. 2081-2100 ◽  
Author(s):  
Sandra Coumar ◽  
Romain Joussot ◽  
Jean Denis Parisse ◽  
Viviana Lago

Purpose The purpose of this paper is to describe experimental and numerical investigations focussed on the shock wave modification induced by a dc glow discharge. The model is a flat plate in a rarefied Mach 2 air flow, equipped with a plasma actuator composed of two electrodes. The natural flow without actuation exhibits a shock wave with a hyperbolic shape. When the discharge is on, the shock wave shape remains hyperbolic but the shock wave is pushed forward, leading to an increase in the shock wave angle. In order to discriminate thermal effects from purely plasma ones, the plasma actuator is then replaced by an heating element. Design/methodology/approach The experimental study is carried out with the super/hypersonic wind tunnel MARHy located at the ICARE Laboratory in Orléans. The experimental configuration with the heating element is simulated with a code using the 2D full compressible Navier-Stokes equations adapted for the rarefied conditions. Findings For heating element temperatures equal to the flat plate wall surface ones with the discharge on, experimental and numerical investigations showed that the shock wave angle was lower with the heating element, only 50 percent of the values got with the plasma actuator, meaning that purely plasma effects must also be considered to fully explain the flow modifications observed. The results obtained with the numerical simulations are then used to calculate the aerodynamic forces, i.e. the drag and the lift. These numerical results are then extrapolated to the plasma actuator case and it was found that the drag coefficient rises up to 13 percent when the plasma actuator is used, compared to only 5 percent with the heating element. Originality/value This paper matters in the topic of atmospheric entries where flow control, heat management and aerodynamic forces are of huge importance.


Chemosphere ◽  
2003 ◽  
Vol 53 (7) ◽  
pp. 779-787 ◽  
Author(s):  
Yen H. Lin ◽  
Jyh Y. Leu ◽  
Chi R. Lan ◽  
P-Hsiu P. Lin ◽  
Fuh L. Chang

Science ◽  
2021 ◽  
Vol 371 (6532) ◽  
pp. 921-925 ◽  
Author(s):  
Mirza Galib ◽  
David T. Limmer

Nitrogen oxides are removed from the troposphere through the reactive uptake of N2O5 into aqueous aerosol. This process is thought to occur within the bulk of an aerosol, through solvation and subsequent hydrolysis. However, this perspective is difficult to reconcile with field measurements and cannot be verified directly because of the fast reaction kinetics of N2O5. Here, we use molecular simulations, including reactive potentials and importance sampling, to study the uptake of N2O5 into an aqueous aerosol. Rather than being mediated by the bulk, uptake is dominated by interfacial processes due to facile hydrolysis at the liquid-vapor interface and competitive reevaporation. With this molecular information, we propose an alternative interfacial reactive uptake model consistent with existing experimental observations.


2022 ◽  
Vol 94 ◽  
pp. 108924
Author(s):  
D. Aljubaili ◽  
L. Chan ◽  
W. Lu ◽  
A. Ooi

Cerâmica ◽  
2018 ◽  
Vol 64 (369) ◽  
pp. 86-90 ◽  
Author(s):  
P. E. A. Lima ◽  
R. S. Angélica ◽  
R. F. Neves

Abstract The kinetic study of Amazon metakaolin dissolution was performed with the application of the shrinking core model for spherical and ‘flat plate’ particles with constant size. The Amazon kaolin was calcinated at 700 ºC in order to produce metakaolin. This metakaolin was leached with 5% excess nitric acid at 70, 80 and 95±3 ºC for 3 h. Samples were collected every 15 min and subjected to aluminum analysis. The acid leaching was a chemically controlled process. The spherical morphology showed better fit than the flat plate particles when taking into account the regression coefficients. 91.58 kJ/mol of activation energy was found as well as an aluminum leaching reaction of the first order. The results found in this work using 5% excess acid and Amazon kaolin were consistent with previous research results using excess acid above 50% and standard kaolin.


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