Comparison of experimental data with numerical modeling of polarization effects on backscattering of waves from a meteor train

1988 ◽  
Vol 31 (12) ◽  
pp. 1026-1031
Author(s):  
V. A. Permyakov ◽  
V. V. Sidorov ◽  
R. G. Khuzyashev
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Polarization Effects ◽  
Meteor Train

scholarly journals Comparison between experimental data and numerical modeling for the natural circulation phenomenon

2011 ◽  
Vol 33 (spe1) ◽  
pp. 227-232 ◽  
Author(s):  
Gaianê Sabundjian ◽  
Delvonei A. de Andrade ◽  
Pedro E. Umbehaun ◽  
Walmir M. Torres ◽  
Luiz A. Macedo ◽  
...  
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Natural Circulation

scholarly journals IDENTIFICATION AND VERIFICATION OF MATERIAL FUNCTIONS OF THE CREEP MODEL UNDER THERMAL RADIATION EFFECTS FOR AUSTENITIC STEEL 1X18H10T

2020 ◽  
Vol 82 (1) ◽  
pp. 89-99
Author(s):  
V.A. Gorokhov
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Creep Rate ◽  
Thermal Radiation ◽  
Neutron Irradiation ◽  
Radiation Effects ◽  
Thermal Creep ◽  
Creep Model ◽  
Material Functions ◽  
Good Agreement

In the present paper, on the basis of the information available in the scientific literature on the thermal creep rate of 1X18H10T austenitic steel under neutron irradiation conditions, the material functions of the thermal creep model implemented and verified in the framework of the certified software for numerical modeling of structural deformation under thermal and thermal radiation effects of UPAKS software are obtained and verified. The list of identifiable material functions of the thermal creep model includes: a function that characterizes the initial creep strain rate, referred to a unit stress level at a given temperature level and stress parameter; the radius of the creep surface, which is a function of temperature; the hardening function, characterizing the change in the initial creep rate from the hardening parameter at a given temperature; a function that takes into account the effect of a fast neutron flux on the creep rate at a given temperature. Using an analytical approximation of experimental data describing the rate of thermal creep of steels under neutron irradiation depending on the stresses, temperature, and flux of fast neutrons, we obtained relations for determining the values of all the functions of the thermal creep model. The value of the radius of the creep surface for a fixed temperature was determined from the condition that the creep deformation for a selected period of time and the neutron flux accumulated during this time will not exceed 0.2%. Using the UPAKS software, the creep model and the obtained material functions implemented in them, numerical simulation of the deformation of 1X18H10T steel under conditions of prolonged thermal load and neutron irradiation was performed. The results of numerical modeling are in good agreement with the analytical dependences that describe the creep of a given material under uniaxial SSS. A numerical creep simulation was also carried out under the assumption of the absence of neutron irradiation. As in the case of neutron irradiation, good agreement is obtained between the calculated and experimental data.

RELATIVISTIC ENERGY, OSCILLATOR STRENGTHS AND TRANSITION RATES OF THE 1s2 2 ln l 1S(m)(n =2–6, m1–5) STATES FOR Be-LIKE SYSTEM

2005 ◽  
Vol 16 (06) ◽  
pp. 951-968 ◽  
Author(s):  
MENG ZHANG ◽  
BING-CONG GOU
Keyword(s):  
Experimental Data ◽  
Energy Levels ◽  
Oscillator Strengths ◽  
Relativistic Energy ◽  
Transition Rates ◽  
Isoelectronic Sequence ◽  
Polarization Effects ◽  
First Order ◽  
Variational Calculations ◽  
First Order Perturbation

Variational calculations are carried out with a multiconfiguration-interaction wave function to obtain the relativistic energies of the 1s2 2 ln l 1 S (m)(n =2–6, m1–5) states for the beryllium isoelectronic sequence (Z =4–10). Relativistic corrections and the mass polarization effects are evaluated with the first-order perturbation theory. The identifications of the energy levels for 1s2 2 ln l 1 S (m)(n =2–6, m1–5) states in the Be-like ions are reported. The oscillator strengths, transition rates and wavelengths are also calculated. The calculated results are compared with other theoretical and experimental data in the literature.

NUMERICAL SIMULATION OF THE LIGHT AIRCRAFT PROPELLER NOISE UNDER STATIC CONDITION

Akustika ◽  
2021 ◽  
pp. 100-106
Author(s):  
sergey Timushev ◽  
Alexey Yakovlev ◽  
Petr Moshkov
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Modeling ◽  
Vortex Method ◽  
Static Condition ◽  
Semiempirical Model ◽  
Calculation Methods ◽  
Propeller Noise ◽  
Calculation Results ◽  
Static Conditions

The problem of simulation the noise generated during the operation of the propeller is considered. Calculation methods are described and numerical simulation of the noise of a light aircraft propeller by the acoustic-vortex method is performed. The results of numerical modeling of the tonal components of the propeller noise when operating under static conditions are compared with experimental data and calculation results based on a semiempirical model.

scholarly journals Study of the Impact of PV-Thermal and Nanofluids on the Desalination Process by Flashing

2020 ◽  
Vol 3 (1) ◽  
pp. 10
Author(s):  
Samuel Sami
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Solar System ◽  
Solar Radiation ◽  
Base Fluid ◽  
Control Volume ◽  
Proposed Model ◽  
Finite Control ◽  
The Impact ◽  
Mathematical And Numerical Modeling

In this study, a mathematical and numerical modeling of the photovoltaic (PV)-thermal solar system to power the multistage flashing chamber process is presented. The proposed model was established after the mass and energy conservation equations written for finite control volume were integrated with properties of the water and nanofluids. The nanofluids studied and presented herein are Ai2O3, CuO, Fe3O4, and SiO2. The multiple flashing chamber process was studied under various conditions, including different solar radiation levels, brine flows and concentrations, and nanofluid concentrations as well as flashing chamber temperatures and pressures. Solar radiation levels were taken as 500 w/m2, 750 w/m2, 1000 w/m2, and finally, 1200 w/m2. The nanofluid volumetric concentrations considered varied from 1% to 20%. There is clear evidence that the higher the solar radiation, the higher the flashed flow produced. The results also clearly show that irreversibility is reduced by using nanofluid Ai2O3 at higher concentrations of 10% to 20% compared to water as base fluid. The highest irreversibility was experienced when water was used as base fluid and the lowest irreversibility was associated with nanofluid SiO2. The irreversibility increase depends upon the type of nanofluid and its thermodynamic properties. Furthermore, the higher the concentration (e.g., from 10% to 20% of Ai2O3), the higher the availability at the last flashing chamber. However, the availability is progressively reduced at the last flashing chamber. Finally, the predicted results compare well with experimental data published in the literature.

Experimental and Numerical Investigation of Dynamic Impact on Universal Breakaway Steel Post

2019 ◽  
Author(s):  
Javad Mehrmashhadi ◽  
Mojdeh A. Pajouh ◽  
John D. Reid
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Dynamic Impact ◽  
Roadside Safety ◽  
Impact Performance ◽  
Component Testing ◽  
Long Span ◽  
Finite Element Package ◽  
The Impact

Abstract A closed guardrail system, known as “bullnose” guardrail system, was previously developed to prevent out-of-control vehicles from falling into the elephant trap. The bullnose guardrail system originally used Controlled Release Terminal (CRT) wood posts to aid in the energy absorption of the system. However, the use of CRT had several drawbacks such as grading and the need for regular inspections. Universal Breakaway Steel Post (UBSP) was then developed by the researchers at Midwest Roadside Safety Facility as a surrogate for CRT. In this study, the impact performance of UBSP on the weak-axis and strong-axis was studied through numerical modeling and component testing (bogie testing). A numerical model was developed using an advanced finite element package LS-DYNA to simulate the impact on UBSP. The numerical results were compared to experimental data. Further research on soil models was recommended. The numerical model will be used to investigate other applications for UBSP such as the Midwest Guardrail System (MGS) long span system, guardrail end terminal designs, or crash cushions.

Ballistic Impact Experiments and Numerical Modelling of Parts of Sandwich Armor

2015 ◽  
Vol 751 ◽  
pp. 211-216
Author(s):  
Vít Sháněl ◽  
Miroslav Španiel
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Numerical Modelling ◽  
Numerical Simulations ◽  
Composite Sandwich ◽  
Modeling Approaches ◽  
Ballistic Protection ◽  
Composite Armor ◽  
Proper Material ◽  
Impact Experiments

This paper presents some experimental results of a bullet impact on composite armor together with numerical modeling approaches. The development of light composite sandwiches for ballistic protection is the target of a project in terms of which the research is being conducted. Traditionally, a vehicle ballistic protection is mainly achieved through metal-based armor which is extremely heavy, hence the increasing popularity of composite sandwiches. Numerical simulations allow for a reduction of the number of experiments needed to obtain appropriate design of ballistic protection, but they require verified modeling approaches and proper material data. Therefore, different modelling approaches for both parts of the composite sandwich have been tested and possibilities to adjust these models to experimental data were investigated.

The elastic scattering of slow electrons by neon and argon

1966 ◽  
Vol 294 (1437) ◽  
pp. 160-174 ◽  
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Energy Range ◽  
Orbital Method ◽  
Polarization Effects ◽  
Polarization Contribution ◽  
Slow Electrons ◽  
Good Agreement

The theory of the scattering of electrons by neon and argon in the energy range 0 to 13.6 eV is worked out with allowance for both exchange and polarization effects. The polarized orbital method introduced by Temkin has been used to estimate the polarization contribution and good agreement is obtained with the experimental data, right down to the lowest energies. Inclusion of exchange alone is not sufficient.

Numerical modeling of deposition-release mechanisms in long-term filtration: validation from experimental data

2014 ◽  
Vol 342 (12) ◽  
pp. 739-746 ◽  
Author(s):  
Hui Wang ◽  
Abdellah Alem ◽  
Huaqing Wang ◽  
Anthony Beaudoin
Keyword(s):  
Experimental Data ◽  
Numerical Modeling ◽  
Release Mechanisms

scholarly journals Modeling of Laminar Flows in Rough-Wall Microchannels

2005 ◽  
Vol 128 (4) ◽  
pp. 734-741 ◽  
Author(s):  
R. Bavière ◽  
G. Gamrat ◽  
M. Favre-Marinet ◽  
S. Le Person
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Numerical Modeling ◽  
Pressure Drop ◽  
Analytical Model ◽  
Analytical Approach ◽  
Laminar Flows ◽  
Numerical Results ◽  
Rough Wall ◽  
Relative Roughness

Numerical modeling and analytical approach were used to compute laminar flows in rough-wall microchannels. Both models considered the same arrangements of rectangular prism rough elements in periodical arrays. The numerical results confirmed that the flow is independent of the Reynolds number in the range 1–200. The analytical model needs only one constant for most geometrical arrangements. It compares well with the numerical results. Moreover, both models are consistent with experimental data. They show that the rough elements drag is mainly responsible for the pressure drop across the channel in the upper part of the relative roughness range.

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