scholarly journals Diagnostic Relations Between Pressure and Entropy Perturbations for Acoustic and Entropy Modes

2021 ◽  
Author(s):  
Sergey Leble ◽  
Ekaterina Smirnova
Keyword(s):  
Numerical Modeling ◽  
Numerical Experiment ◽  
Numerical Data ◽  
Equilibrium Temperature ◽  
Problem Solution ◽  
Vertical Coordinate ◽  
Atmospheric Disturbances ◽  
Individual Profiles ◽  
Analytical Expressions ◽  
Prospective Model

Diagnostics and decomposition of atmospheric disturbances in a planar flow are considered and applied to numerical modeling results with the direct possibility to use in atmosphere monitoring especially in such strong events which follow magnetic storms. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on a vertical coordinate, that seriously complicates the problem solution. The relations connecting perturbations for acoustic and entropy modes are analytically established and led to the solvable diagnostic equations. These perturbation structures, found as the equation solutions specify acoustic and entropy modes in an arbitrary stratified gas under the condition of stability. These time-independent diagnostic relations link gas perturbation variables of the acoustic and the entropy modes. Hence, they provide the ability to decompose the total vector of perturbations into acoustic and non-acoustic (entropy) parts uniquely at any instant within the all accessible heights range. As a prospective model, we consider the diagnostics at the height interval [120;180] km, where the equilibrium temperature of a gas depends linearly on the vertical coordinate. For such a heights range it is possible to proceed with analytical expressions for pressure and entropy perturbations of gas variables. Individual profiles of acoustic and entropy parts for some data, obtained by numerical experiment, are illustrated by the plots for the pure numerical data against ones obtained by the model. The total energy of a flow is determined for both approaches and its height profiles are compared.

scholarly journals Diagnostic Relations Between Pressure and Entropy Perturbations for Acoustic and Entropy Modes

2021 ◽  
Author(s):  
Sergey Leble ◽  
Ekaterina Smirnova
Keyword(s):  
Numerical Modeling ◽  
Numerical Experiment ◽  
Numerical Data ◽  
Equilibrium Temperature ◽  
Problem Solution ◽  
Vertical Coordinate ◽  
Atmospheric Disturbances ◽  
Individual Profiles ◽  
Analytical Expressions ◽  
Prospective Model

Diagnostics and decomposition of atmospheric disturbances in a planar flow are considered and applied to numerical modeling results with the direct possibility to use in atmosphere monitoring especially in such strong events which follow magnetic storms. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on a vertical coordinate, that seriously complicates the problem solution. The relations connecting perturbations for acoustic and entropy modes are analytically established and led to the solvable diagnostic equations. These perturbation structures, found as the equation solutions specify acoustic and entropy modes in an arbitrary stratified gas under the condition of stability. These time-independent diagnostic relations link gas perturbation variables of the acoustic and the entropy modes. Hence, they provide the ability to decompose the total vector of perturbations into acoustic and non-acoustic (entropy) parts uniquely at any instant within the all accessible heights range. As a prospective model, we consider the diagnostics at the height interval [120;180] km, where the equilibrium temperature of a gas depends linearly on the vertical coordinate. For such a heights range it is possible to proceed with analytical expressions for pressure and entropy perturbations of gas variables. Individual profiles of acoustic and entropy parts for some data, obtained by numerical experiment, are illustrated by the plots for the pure numerical data against ones obtained by the model. The total energy of a flow is determined for both approaches and its height profiles are compared.

scholarly journals Diagnostic Relations between Pressure and Entropy Perturbations for Acoustic and Entropy Modes

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1164
Author(s):  
Sergey Leble ◽  
Ekaterina Smirnova
Keyword(s):  
Large Scale ◽  
Numerical Data ◽  
Equilibrium Temperature ◽  
Vertical Profiles ◽  
Vertical Coordinate ◽  
Atmospheric Disturbances ◽  
Individual Profiles ◽  
Atmospheric Phenomena ◽  
Analytical Expressions ◽  
Prospective Model

Diagnostics and decomposition of atmospheric disturbances in a planar flow are considered and applied to numerical modelling with the direct possibility to use in atmosphere monitoring especially in such strong events which follow magnetic storms and other large scale atmospheric phenomena. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on a vertical coordinate, which essentially complicates the diagnostics. The relations connecting perturbations for acoustic and entropy (stationary) modes are analytically established and led to the solvable diagnostic equations. These equations specify acoustic and entropy modes in an arbitrary stratified gas under the condition of stability. The diagnostic relations are independent of time and specify the acoustic and the entropy modes. They provide the ability to decompose the total vector of perturbations into acoustic and non-acoustic (entropy) parts uniquely at any instant within the total accessible heights range. As a prospective model, we consider the diagnostics at the height interval 120–180 km, where the equilibrium temperature of a gas depends linearly on the vertical coordinate. For such a heights range it is possible to proceed with analytical expressions for pressure and entropy perturbations of gas variables. Individual profiles of acoustic and entropy parts for some data are illustrated by the plots for the pure numerical data against those obtained by the model. The total energy of a flow is determined for both approaches and its vertical profiles are compared.

scholarly journals The Analytical Study of the Value of Adhesion of Cement Gel between Reinforcement and Concrete

2020 ◽  
Vol 26 (3) ◽  
pp. 483-495
Author(s):  
A. N. Nikolyukin ◽  
◽  
V. P. Yartsev ◽  
S. A. Mamontov ◽  
I. I. Kolomnikova ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Numerical Modeling ◽  
Numerical Experiment ◽  
Bearing Capacity ◽  
Analytical Study ◽  
Bonding Process ◽  
Periodic Profile

Disruption of the adhesion of reinforcement to concrete causes significant deformation of the structure, which can subsequently lead to the loss of its bearing capacity. There is a need to study the bonding process between concrete and reinforcement under various influences. The results of a numerical experiment on pulling out reinforcement of periodic profile from concrete are presented. A mathematical model to study the processes taking place in the field of embedding reinforcement in concrete has been built. The results of numerical modeling are described.

scholarly journals A climatological view of the vertical stratification of RH, O<sub>3</sub> and CO within the PBL and at the interface with free troposphere as seen by IAGOS aircraft and ozonesondes at northern mid-latitudes over 1994–2016

2018 ◽  
Author(s):  
Hervé Petetin ◽  
Bastien Sauvage ◽  
Herman G. J. Smit ◽  
François Gheusi ◽  
Fabienne Lohou ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Potential Temperature ◽  
Vertical Stratification ◽  
Vertical Profiles ◽  
Free Troposphere ◽  
Diurnal Variability ◽  
Vertical Coordinate ◽  
Mixing Ratios ◽  
Seasonal And Diurnal Variations ◽  
Individual Profiles

Abstract. This paper investigates in an innovative way the climatological vertical stratification of relative humidity (RH) and ozone (O3) and carbon monoxide (CO) mixing ratios within the planetary boundary layer (PBL) and at the interface with the free troposphere (FT). The climatology includes all vertical profiles available at northern mid-latitudes over the period 1994–2016 in both IAGOS (In-service Aircraft for a Global Observing System) and WOUDC (World Ozone and Ultraviolet Radiation Data Centre) databases, which represents more than 90,000 vertical profiles. For all individual profiles, apart from the specific case of surface-based temperature inversions (SBIs), the PBL height is estimated following the elevated temperature inversion (EI) method. Several features of both SBIs and EIs are analysed, including their diurnal and seasonal variations. Based on these PBL height estimates (denoted h), the original approach introduced in this paper consists in building a so-called PBL-referenced vertical distribution of O3, CO and RH by averaging all individual profiles beforehand expressed as a function of z/h rather than z (with z the altitude). Using this vertical coordinate system allows to highlight the features existing at the PBL-FT interface that would have been smoothed otherwise. Results demonstrate that the frequently assumed well-mixed PBL remains an exception for both chemical species. Within the PBL, CO profiles are characterized by a mean vertical stratification (here defined as the standard deviation of the CO profile between the surface and the PBL top, normalized by the mean) of 11 %, with moderate seasonal and diurnal variations. A higher vertical stratification is observed for O3 mixing ratios (18 %), with stronger seasonal and diurnal variability (from ~ 10 % in spring/summer midday/afternoon to ~ 25 % in winter/fall night). This vertical stratification is distributed heterogeneously in the PBL with stronger vertical gradients observed at both the surface (due to dry deposition and titration by NO for O3; and due to surface emissions for CO) and the PBL-FT interface. These gradients vary with the season from lowest values in summer to highest ones in winter. Contrary to CO, the O3 vertical stratification was found to vary with the surface potential temperature following an interesting bell shape with weakest stratification for both lowest (typically negative) and highest temperatures, which could be due to a much lower O3 dry deposition under the presence of snow. Therefore, results demonstrate that EIs act as a geophysical interface separating air masses of distinct chemical composition and/or chemical regime. This is further supported by the analysis of the correlation of O3 and CO mixing ratios between the different altitude levels in the PBL and FT (the so-called vertical autocorrelation). Results indeed highlight lower correlations apart from the PBL-FT interface and higher correlations within each of the two atmospheric compartments (PBL and FT).

scholarly journals NUMERICAL MODELING OF COMPOSITE FITTINGS FOR CLUTCHING WITH CONCRETE

2019 ◽  
Vol 4 (5) ◽  
pp. 56-65 ◽  
Author(s):  
А. Николюкин ◽  
A. Nikolyukin ◽  
В. Ярцев ◽  
Viktor Yarcev ◽  
И. Коломникова ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Numerical Modeling ◽  
Reinforced Concrete ◽  
Numerical Experiment ◽  
Bearing Capacity ◽  
Static Loads ◽  
Reinforcing Bar ◽  
Numerical Studies ◽  
Accumulation Of Defects ◽  
Periodic Profile

Reinforced concrete is one of the most common materials in construction. Constructions made of this material have a high bearing capacity; well perceived dynamic and static loads. This is ensured by the adhesion between the reinforcing bar and concrete. The amount of adhesion is made from a number of different factors formed in the region of the conventional surface of interaction of reinforcement with concrete. It is implied that even if any reinforcement is used, materials come into contact over the surface, which can collapse depending on the load. Violation of the clutch causes significant deformation of the structure, which subsequently leads to a loss of the bearing capacity of the element. Therefore, there is a need to study the magnitude of the adhesion between concrete and reinforcement under various influences. This article describes the results of a numerical experiment on pulling out fiberglass reinforcement of a periodic profile from concrete. A mathematical model is constructed, which allows to study the accumulation of defects and the destruction of reinforcement in the area of concrete fixing. The results of numerical studies are considered.

scholarly journals Assessment of Influence of Residential Area Planning Structure on Air Quality Using Numerical Modeling

2021 ◽  
Vol 1203 (3) ◽  
pp. 032040
Author(s):  
Svetlana Valger ◽  
Anastasia Maslova
Keyword(s):  
Numerical Modeling ◽  
Air Quality ◽  
Computational Experiment ◽  
Numerical Study ◽  
Numerical Data ◽  
Residential Area ◽  
Ansys Software ◽  
Prevailing Wind Direction ◽  
High Concentrations ◽  
Area Planning

Abstract Numerical study of the aeration of a new urban microdistrict located along a highway in Novosibirsk, Russia, was performed. The main goal of the paper was to assess whether the architectural and planning structure of the new microdistrict is optimal in terms of aeration and air quality. A scenario of particulate matter (PM10) transfer in the vicinity of the microdistrict is reproduced. Numerical modeling is performed for the prevailing wind direction. 3D numerical simulation was carried out using the Revit software to build the CAD model of the residential area and the ANSYS software was used to perform a computational experiment. Based on the calculations, numerical data were obtained on the wind speed and on PM10 concentration fields in the residential area. Favorable and unfavorable zones of the microdistrict in terms of high concentrations of PM10 at the pedestrian zones were described.

Amplitude responses of thin beds: Sinusoidal approximation versus Ricker approximation

Geophysics ◽  
1995 ◽  
Vol 60 (1) ◽  
pp. 223-230 ◽  
Author(s):  
Hai‐Man Chung ◽  
Don C. Lawton
Keyword(s):  
Numerical Modeling ◽  
Normal Incidence ◽  
Reflection Coefficients ◽  
Amplitude Dependence ◽  
Dominant Wavelength ◽  
Amplitude Response ◽  
Analytical Expression ◽  
Ricker Wavelet ◽  
Analytical Expressions

The amplitude response of a thin bed with arbitrary upper and lower normal incidence reflection coefficients is studied. Two analytical expressions for the normal incidence amplitude response as a function of the thickness are derived and are both valid for weak reflectivities and for thicknesses below [Formula: see text], where [Formula: see text] is the dominant wavelength. The first expression is based on the substitution of a cosine wave for the source wavelet, and the second is based directly on the analytical expression for a Ricker wavelet. The results calculated from these two expressions are compared to numerical modeling results for a Ricker wavelet for several models. We found that the differences between the two expressions are small, and both are good approximations. Above the [Formula: see text] thickness, the percentage differences increase rapidly for both expressions, implying that the thin‐bed assumptions in both derivations break down rapidly beyond the [Formula: see text] thickness. Below the [Formula: see text] thickness, except in the case where the two reflection coefficients are equal in magnitude but opposite in sign, the amplitude dependence on the thickness is nonlinear.

Detection of 3-D inhomogeneities of the medium at magnetotelluric sounding in the Arctic (numerical experiment)

2019 ◽  
Vol 220 (2) ◽  
pp. 1340-1351
Author(s):  
Valery V Plotkin ◽  
Vladimir S Mogilatov ◽  
Vladimir A Gurev ◽  
Vladimir V Potapov
Keyword(s):  
Electric Field ◽  
Numerical Experiment ◽  
Field Component ◽  
Synthetic Data ◽  
Field Potential ◽  
Magnetotelluric Sounding ◽  
The Arctic ◽  
Problem Solution ◽  
Ice Surface ◽  
Tm Mode

SUMMARY The magnetotelluric sounding (MTS) conducted on drifting ice floes in the Arctic is of particular interest for detection of 3-D inhomogeneities in crustal conductivity. Their manifestations in behaviour of standard magnetotelluric curves are shielded by the well conducting layers of seawater and sediment. As target objects, these inhomogeneities are shown as small changes (only hundredths of per cent) in apparent resistivity, and as very weak variations of vertical magnetic field component. Therefore, accounting for additional data on the vertical electric field component or the electric field potential of the transverse magnetic (TM) mode is of interest. For recording the TM-mode potential, we offer to use the circular electric dipole (CED) located on the ice surface as a receiver in MTS. We investigate possibilities of crustal 3-D inhomogeneity detection using the TM-mode potential received with the CED. A numerical experiment showed that the potential of electric field of the TM-mode on the ice surface reaches values suitable for detection. Examples of the inverse problem solution using synthetic data on the TM-mode field are presented. We found that the information on the depth of 3-D object could be obtained by the analytical continuation of the profile data on the TM-mode potential. Using the MTU-5 Phoenix Geophysics stations for the CED system, we carried out preliminary measurements on the ice surface on the Ob river. We checked the measurement results of the TM-mode potential using the MTS data obtained earlier near the CED system. We compared results of the TM-mode potential calculation for the found 3-D-medium model to the CED experimental data. Our results showed that the potential dependences on the period measured by the СED and those obtained for the 3-D model have similar characteristics. We believe recording the TM-mode potential in the Arctic allows to reveal the existence and characteristics of crustal conductivity 3-D heterogeneities.

scholarly journals Effects of Geometry and Hydraulic Characteristics of Shallow Reservoirs on Sediment Entrapment

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1725 ◽  
Author(s):  
Hamidreza Zahabi ◽  
Mohammadamin Torabi ◽  
Ebrahim Alamatian ◽  
Mehdi Bahiraei ◽  
Marjan Goodarzi
Keyword(s):  
Numerical Modeling ◽  
Software Package ◽  
Reasonable Agreement ◽  
Numerical Data ◽  
Considerable Effect ◽  
Hydraulic Characteristics ◽  
Eddy Simulation ◽  
Large Eddy ◽  
3D Software ◽  
Shallow Reservoirs

Sediment and deposition are among the main problems in dam engineering and other related fields. Because of the numerous advantages of numerical modeling, effects of different geometries of reservoirs on the flow pattern and deposition of sediments are investigated using the finite volume based Flow-3D software package. In this study, three rectangular reservoirs with different dimensional ratios are simulated using the large eddy simulation (LES) turbulence model. To validate the numerical modeling, existing experimental data is used. Results indicate that Flow-3D can accurately simulate flow and sediment deposition in the reservoirs, and the numerical data are in reasonable agreement with the experimental results. Numerical efforts showed that the amount of deposition in reservoirs is significantly dependent on the geometry. Among the modeled reservoirs, the 6 × 4 m one has the best performance. Moreover, it can be said that changing the position of the flow’s inlet and outlet of the reservoir does not have a considerable effect on increasing its efficiency.

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