Nudging of vertical profiles of meteorological parameters in one-dimensional atmospheric model: A step towards improvements in numerical simulations

2008 ◽  
Vol 43 (4) ◽  
pp. 165-173 ◽  
Author(s):  
D. Bala Subrahamanyam ◽  
S. Indira Rani ◽  
Radhika Ramachandran ◽  
P. K. Kunhikrishnan
Keyword(s):  
Numerical Simulations ◽  
Meteorological Parameters ◽  
Atmospheric Model ◽  
Vertical Profiles ◽  
One Dimensional

scholarly journals CFD Simulation and Experimental Measurements of Radon Distribution in a Traditional Hammam

2021 ◽  
Vol 39 (3) ◽  
pp. 963-968
Author(s):  
Rabi Rabi ◽  
Lhoucine Oufni ◽  
El-Hocine Youssoufi ◽  
Khamiss Cheikh ◽  
Hamza Badry ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Numerical Simulations ◽  
Indoor Air ◽  
Meteorological Parameters ◽  
Rate Increase ◽  
Cfd Simulation ◽  
Ventilation Rate ◽  
Maximum Deviation ◽  
Experimental Measurements ◽  
The Public

Radon natural is the main cause of lung cancer in non-smokers. Therefore, the study of the behavior of radon and its descendants in indoor air is of the highest importance, in order to limit the risk of radiation dose due to inhalation of radon by members of the public. This article focuses to study the effects of meteorological parameters on the concentration and distribution of radon in a traditional hammam by both numerical simulations and experiments. The results of the numerical simulations are qualitative and show that the concentration and distribution of radon decrease when the ventilation rate increase, as well as, when the temperature increases, however, it increases with the increase in relative humidity. The results obtained by the numerical simulations were in agreement with those obtained experimentally with a maximum deviation of 7%. Numerical simulations allow a better estimate of the distribution of radon in indoor air.

scholarly journals Parabolic bursting, spike-adding, dips and slices in a minimal model

2019 ◽  
Vol 14 (4) ◽  
pp. 406
Author(s):  
Mathieu Desroches ◽  
Jean-Pierre Francoise ◽  
Martin Krupa
Keyword(s):  
Qualitative Analysis ◽  
Numerical Simulations ◽  
Phase Portrait ◽  
Minimal Model ◽  
Bifurcation Theory ◽  
Minimal System ◽  
Dimensional System ◽  
Slow Flow ◽  
Van Der Pol ◽  
One Dimensional

A minimal system for parabolic bursting, whose associated slow flow is integrable, is presented and studied both from the viewpoint of bifurcation theory of slow-fast systems, of the qualitative analysis of its phase portrait and of numerical simulations. We focus the analysis on the spike-adding phenomenon. After a reduction to a periodically forced one-dimensional system, we uncover the link with the dips and slices first discussed by J.E. Littlewood in his famous articles on the periodically forced van der Pol system.

scholarly journals A spectral nudging method for the ACCESS1.3 atmospheric model

2015 ◽  
Vol 8 (6) ◽  
pp. 1645-1658 ◽  
Author(s):  
P. Uhe ◽  
M. Thatcher
Keyword(s):  
Relaxation Method ◽  
Atmospheric Model ◽  
Care Needs ◽  
One Dimensional ◽  
Spectral Nudging ◽  
Earth Systems ◽  
Australian Community ◽  
Effectiveness And Efficiency ◽  
Convolution Approach ◽  
The Uk

Abstract. A convolution-based method of spectral nudging of atmospheric fields is developed in the Australian Community Climate and Earth Systems Simulator (ACCESS) version 1.3 which uses the UK Met Office Unified Model version 7.3 as its atmospheric component. The use of convolutions allow for flexibility in application to different atmospheric grids. An approximation using one-dimensional convolutions is applied, improving the time taken by the nudging scheme by 10–30 times compared with a version using a two-dimensional convolution, without measurably degrading its performance. Care needs to be taken in the order of the convolutions and the frequency of nudging to obtain the best outcome. The spectral nudging scheme is benchmarked against a Newtonian relaxation method, nudging winds and air temperature towards ERA-Interim reanalyses. We find that the convolution approach can produce results that are competitive with Newtonian relaxation in both the effectiveness and efficiency of the scheme, while giving the added flexibility of choosing which length scales to nudge.

scholarly journals Tomographic retrievals of ozone with the OMPS Limb Profiler: algorithm description and preliminary results

2018 ◽  
Vol 11 (4) ◽  
pp. 2375-2393 ◽  
Author(s):  
Daniel J. Zawada ◽  
Landon A. Rieger ◽  
Adam E. Bourassa ◽  
Douglas A. Degenstein
Keyword(s):  
Polar Vortex ◽  
Retrieval Algorithm ◽  
Vertical Profiles ◽  
Two Dimensional ◽  
One Dimensional ◽  
Preliminary Results ◽  
Horizontal Gradients ◽  
The Mean ◽  
The One

Abstract. Measurements of limb-scattered sunlight from the Ozone Mapping and Profiler Suite Limb Profiler (OMPS-LP) can be used to obtain vertical profiles of ozone in the stratosphere. In this paper we describe a two-dimensional, or tomographic, retrieval algorithm for OMPS-LP where variations are retrieved simultaneously in altitude and the along-orbital-track dimension. The algorithm has been applied to measurements from the center slit for the full OMPS-LP mission to create the publicly available University of Saskatchewan (USask) OMPS-LP 2D v1.0.2 dataset. Tropical ozone anomalies are compared with measurements from the Microwave Limb Sounder (MLS), where differences are less than 5 % of the mean ozone value for the majority of the stratosphere. Examples of near-coincident measurements with MLS are also shown, and agreement at the 5 % level is observed for the majority of the stratosphere. Both simulated retrievals and coincident comparisons with MLS are shown at the edge of the polar vortex, comparing the results to a traditional one-dimensional retrieval. The one-dimensional retrieval is shown to consistently overestimate the amount of ozone in areas of large horizontal gradients relative to both MLS and the two-dimensional retrieval.

Revisiting V-3 Canon for the Application of Single Stage Gas Gun

2017 ◽  
Author(s):  
Arun Tom Mathew ◽  
Tirumala Rao Koka ◽  
Murali Krishnan Payangapadan
Keyword(s):  
Design Of Experiments ◽  
Numerical Simulations ◽  
Response Surface ◽  
Three Dimensional ◽  
Optimal Location ◽  
Single Stage ◽  
One Dimensional ◽  
Alternative Design ◽  
Gas Gun ◽  
Gas Guns

Single stage gas guns are typically used for accelerating the projectiles in bird and hail impact tests of aerospace components and engines. In this paper an alternative design for single stage gas gun is studied, which is derived from V3 canon. Three dimensional numerical simulations is carried out for the optimal secondary connection angle with the main barrel. A one dimensional code is developed for the V3 canon based design. Design of experiments conducted to find the response surface for the optimal location of the secondary connection, volume and pressure of the secondary tank.

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