Some Aspects of Acoustic Emissions during the Launch of a Space Rocket in Research of Earth by Satellites

2021 ◽  
Author(s):  
Galyna Sokol ◽  
Vladyslav Kotlov ◽  
Victor Frolov ◽  
Volodymyr Syrenko ◽  
Volodymyr Dudnikov
Keyword(s):  
Acoustic Radiation ◽  
Acoustic Emissions ◽  
Experimental Tests ◽  
Acoustic Vibration ◽  
Physical Models ◽  
Acoustic Fields ◽  
Acoustic Vibrations ◽  
Secondary Sources ◽  
Space Rocket ◽  
Plates And Shells

<p>Acoustic fields of various types of radiation and power arise during the rocket’s movement in the atmosphere after the launch. One of the most topical studies here is the analysis and assessment of the infrasonic radiation levels and their impact on the health of the nearby settlements population and the spaceport maintenance personnel. Therefore, it is necessary to identify the features and determine the directions of acoustic radiation research based on existing ideas about the generation, propagation, and impact of infrasound.</p><p>The methodology for researching acoustic radiation during rocket movement includes identifying the primary sources of acoustic vibrations. That is vibrations from a working propulsion system, from the vibrating shell of the rocket case, turbulent vortices in the flow around the rocket case. And also the identification of acoustic vibrations secondary sources arising from the primary vibrations reflection from collisions with obstacles, for example, the launch pad surface type.</p><p>It is necessary to develop physical models of acoustic fields, the nature of which depends primarily on the type of acoustic sources.</p><p>These are the following models:</p><ul><li>point radiation (monopoles);</li> <li>analysis of acoustic fields generated in the environment by force acting on a rigid surface and characterized by the Lamb potential;</li> <li>acoustic radiation and fields during vibrations of plates and shells of various shapes, lengths, and areas;</li> <li>acoustic radiation during the movable environment and solid bodies interaction;</li> <li>acoustic radiation at the jets outflow from nozzles;</li> <li>excitation and propagation of acoustic vibrations inside gas and liquid cavities, taking into account the peculiarities of the shells’ structural schemes, the resonances identification;</li> <li>monochromatic and pulsed radiation.</li> </ul><p>The next step is the creation of mathematical models designed to calculate the acoustic field characteristics (analytical methods, the use of Taylor and Fourier series, numerical programming methods). Mathematical dependences will make it possible to analyze the relationship between the acoustic radiation sources energy characteristics and the characteristics of their acoustic fields. It is important to calculate the acoustic radiation amplitude-frequency characteristics.</p><p>Experimental tests, the development of programs, and methods for measuring the acoustic vibration characteristics are important. At the same time, a list of equipment necessary for measuring acoustic characteristics (instruments, circuits, equipment) is created.</p><p>As a result of physical and mathematical analysis of acoustic vibrations sources, it is possible to develop active and passive methods of damping them. As well as giving recommendations for damping acoustic vibrations.</p>

Research on Vibro-Acoustic Characteristics of Underwater Finite Plate-Shell Structure under Multiple Excitations

2013 ◽  
Vol 834-836 ◽  
pp. 1351-1359
Author(s):  
Yong Yong Zhu
Keyword(s):  
Shell Structure ◽  
Acoustic Radiation ◽  
Radiation Power ◽  
Acoustic Vibration ◽  
Finite Cylinder ◽  
Acoustic Characteristics ◽  
Theory Of Plates ◽  
Plates And Shells ◽  
Vibration Coupling ◽  
Finite Cylindrical Shell

An analysis based on the first kind of Lagranges equations was presented for investigating the vibration and acoustic radiation of underwater finite cylindrical shell with interior plate under multiple excitations. The strain energy and kinetic energy of cylinder and plate were gained by the theory of plates and shells, and the potential energy of excitation and fluid loading was found based on acoustic-vibration coupling, and the connection conditions of plate and cylinder were expressed by Lagrange multipliers, then the vibro-acoustic equations of finite cylinder with interior plate under shafting excitation were established. The influences of excitations and plates position to the vibro-acoustic characteristics were studied by the equations. The results show that the frequency components of plate-shell structure are more complex. For the double excitations on plate, the distance between excitations is larger, the average velocity and sound radiation power are lower, while the radiation efficiency is larger. The modeling and analytical methods adopted in this paper are also available for more complex composite structure.

Studies of Acoustic Characteristics and Their Comparison With Vibration Ones

1995 ◽  
Author(s):  
Alexander E. Ekimov
Keyword(s):  
Transfer Coefficient ◽  
Distributed System ◽  
Acoustic Radiation ◽  
Physical Models ◽  
System Model ◽  
Acoustic Fields ◽  
Transfer Coefficients ◽  
Acoustic Characteristics ◽  
Reciprocity Method ◽  
Force Characteristics

Abstract The present paper gives the methods, schemes and results of experiments based on direct and reciprocal methods of measurements. The use of the reciprocity method made it possible to solve the problem of determining the acoustic characteristics of the distributed system model where vibroactive sources are represented in the form of passive models. It has been shown that the normalized transfer coefficient characterizing a link between force and acoustic fields has the same value both for the model and in nature (in case of their full similarity) that can be used: - to improve the methods of designing and technological manufacturing of models based on the comparison of normalized transfer coefficients obtained for full-scale and physical models; - to forecast the acoustic radiation of some vibroactive mechanisms using the assigned force characteristics and normalized transfer coefficients obtained for a model with the modelling scale taken into account.

scholarly journals ВОЛНОВОЙ ПАРАМЕТР КАК КРИТЕРИЙ В ОСНОВЕ МЕТОДА ИССЛЕДОВАНИЯ АКУСТИЧЕСКИХ ИСТОЧНИКОВ ПРИ СТАРТЕ РАКЕТ

2018 ◽  
pp. 4-12
Author(s):  
Виктор Петрович Фролов ◽  
Галина Ивановна Сокол ◽  
Владислав Юрьевич Котлов
Keyword(s):  
Spherical Wave ◽  
Acoustic Emissions ◽  
Acoustic Power ◽  
Wave Parameter ◽  
Wave Radiation ◽  
Power Calculation ◽  
Acoustic Fields ◽  
Rocket Launch ◽  
Spherical Waves ◽  
Space Rocket

The purpose of this work is to develop a method for determining the types of acoustic sources of radiation and their acoustic fields during the space rockets launch in the first seconds based on the wave parameter values. The main noise source during the space rocket launch is its propulsion system (PS). The cross-section of the nozzle is taken as the oscillation source. The theory of siren sound emission is based on the acoustic power calculation of a jet as a volume sound radiator or a radiator with a space velocity. In the model of a volumetric spherical radiator, the front of a spherical wave is a spherical surface, and the sound rays, according to the definition of the wave front, coincide with the radii of the sphere. As a result of the divergence of waves, the sound intensity decreases with distance from the source. The present work has a prospective character for clarifying the nature of the acoustic fields and for calculating the noise levels from the space rocket launch when designing the cosmodromes. In the requirements for the construction of such structures, the noise impact on the environment of infrasound radiation upon launching launch vehicles is identified. A method for determining the types of acoustic radiation sources during the space rocket launch and their acoustic fields has been developed. The method makes it possible to develop physical models of acoustic fields and apply known mathematical models to calculating their characteristics. The method is applicable for the study of acoustic emissions in the first seconds of the space rocket launch based on the determination of the wave parameter kR and allows us to provide valid data on the levels of sound pressure, intensity and acoustic power at specific points of airspace around the PS in the first seconds of the launch. The character of the acoustic wave radiation from a hole in a specific size gas flue has been studied. To calculate the acoustic characteristics, an algorithm and a program on Java programming language have been developed. Two models of acoustic field generation in the environment are described during the work of a rocket as a plane radiator and spherical waves, depending on the value of the wave parameter kR. A technique for calculating the noise of a remote control in the range for the first 1.5-4 seconds of the space rocket start time is developed

scholarly journals Analysis of the NUPEC PSBT Tests with FLICA-OVAP

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Matteo Bucci ◽  
Philippe Fillion
Keyword(s):  
Nuclear Power ◽  
Experimental Tests ◽  
Physical Models ◽  
Rod Bundles ◽  
Two Phase ◽  
Experimental Database ◽  
Boiling Crisis ◽  
Power Increase ◽  
Relevant Role

This paper discusses the results of a computational activity devoted to the prediction of two-phase flows in subchannels and in rod bundles. The capabilities of the FLICA-OVAP code have been tested against an extensive experimental database made available by the Japanese Nuclear Power Energy Corporation (NUPEC) in the frame of the PWR subchannel and bundle tests (PSBT) international benchmark promoted by OECD and NRC. The experimental tests herein addressed involve void fraction distributions and boiling crisis phenomena in rod bundles with uniform and nonuniform heat flux conditions. Both steady-state and transient scenarios have been addressed, including power increase, flow reduction, temperature increase, and depressurization, representative of PWR thermal-hydraulics conditions. After a brief description of the main features of FLICA-OVAP, the relevant physical models available within the code are detailed. Results obtained in the different tests included in the PSBT void distribution and DNB benchmarks are therefore reported. The relevant role of selected physical models is discussed.

A method of reproducing complex, multi-object anatomical structures

2017 ◽  
Vol 23 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Tomasz Kudasik ◽  
Slawomir Miechowicz
Keyword(s):  
Patent Protection ◽  
Soft Tissues ◽  
Patent Application ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Medical Problem ◽  
Physical Models ◽  
Anatomical Structures ◽  
Content Type ◽  
3D Cad

Purpose This paper aims to present a method of reproducing multi-object structures from materials of diverse physical properties with the use of models fabricated by means of rapid prototyping (RP) techniques. Design/methodology/approach A process of modelling complex anatomical structures of soft tissues and bones using mandible models as examples was described. The study is based on data acquired through standard computed tomography. Physical models of examined objects were fabricated with RP technology from a 3D-CAD virtual model. Findings In the analysis of complex medical issues, beside numerical methods, one can simultaneously make use of experimental tests to verify obtained results. In the case of experimental tests, it is necessary to fabricate physical models with appropriate material properties. RP techniques used in the method ensure accurate reproduction of the external shape of the fabricated model, whereas consecutive stages allow us to construct moulds and create internal structures within a finished model by wax cast models. Practical implications The application of a physical RP model makes the identification of medical problem more efficient and the reconstruction of pathological alterations for experimental tests clearer. It prevents the simplification of assumptions to experimental analysis. The approach may reduce costs of fabricating models for experimental studies and offers the possibility of using materials of desired properties. Originality/value The approach developed by the authors and presented in this paper was submitted for patent protection as “A Method of Reconstructing Medical Models with Internal Structure and the Use of Materials of Diverse properties” – patent application no. P.398644.

scholarly journals ON THE RESULTS OF EXPERIMENTAL STUDIES OF THE PHYSICAL PROCESS OF GENERATING SOUND VIBRATIONS BEATS IN CLOSED AIR CAVITIES OF TECHNICAL ROOMS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 17-23
Author(s):  
Mikhail Fesina ◽  
Igor Deryabin ◽  
Gorina Larisa
Keyword(s):  
Physical Process ◽  
Acoustic Radiation ◽  
Experimental Studies ◽  
Acoustic Vibration ◽  
Physical Processes ◽  
Process Creation ◽  
Limited Frequency ◽  
Air Cavities ◽  
Distinct Features ◽  
Experimental Researches

This paper gives the results of experimental researches for producing physical processes of acoustic vibration beats, which are spread in a free and in a diffused field of enclosed air volumes in technical rooms of different types. There are defined general regularities and distinct features of forming the physical processes of acoustic vibration beats. A limited frequency range of beats production which includes two different frequency ranges of dynamic frequency interactions with close values of sound frequencies are found out. Sufficiency of frequency detuning of two independent sources of acoustic radiation which exclude physical process creation of sound frequency beats is defined.

Acoustic radiation mode shapes for control of plates and shells

2013 ◽  
Vol 133 (5) ◽  
pp. 3385-3385 ◽  
Author(s):  
William R. Johnson ◽  
Pegah Aslani ◽  
Daniel R. Hendricks
Keyword(s):  
Acoustic Radiation ◽  
Mode Shapes ◽  
Radiation Mode ◽  
Plates And Shells

scholarly journals Study of Unsteady Airflow in Muffler and Air Box Equivalent Geometries

2013 ◽  
Author(s):  
Nicolas-Ivan Hatat ◽  
François Lormier ◽  
David Chalet ◽  
Pascal Chesse
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Internal Combustion ◽  
Physical Models ◽  
One Dimensional ◽  
1D Modeling ◽  
Air Intake ◽  
And Performance

The Internal Combustion Engines (ICE) are inherently sources of the flow’s unsteadiness in the intake and exhaust ducts. Unsteady flow has a direct impact on the engine’s behavior and performance by influencing the filling and emptying of the cylinder. Air intake boxes as well as muffler geometries, which are very commonly used on the two-wheeled vehicles, have an impact on pressure levels and so, on air filling and performances levels. Thus, the purpose of this paper is to identify and analyze different typical geometries of these elements (air box and muffler) by comparing the test bench results with those obtained by 3D and 1D calculations. In this way, it is possible to establish a methodology for modeling the air box and muffler based on experimental tests and the development of 3D and then 1D model. In a beginning, studies consist in describing the geometry of the air box and muffler using a combination of tubes and simple volumes. During one-dimensional simulations, the gases properties in a volume must be calculated taking into account a method of filling and emptying. Under transient conditions, the pipe element is considered essentially as one-dimensional. The gas dynamic is described by a system of equations: the equations of continuity, momentum and energy. In the three-dimensional case, all tubes and volumes are meshed and solved using various physical models, equations and hypotheses that will be detailed subsequently. The study is performed on a shock tube bench. One of the main points is that this type of experimental test allows to test easily different pressure ratios, different geometries and to measure direct and inverse flow. In this way, the propagation of a shock wave is studied in our different geometries and is compared to the pressure signals obtained with 1D and 3D simulations. Once the 1D modeling is obtained, it must be validated in order to be applied in a simulation for Internal Combustion Engine. Validation will be done by direct comparison of results at each stage to ensure that the models and assumptions used in the calculations are correct.

Particle Damping for Passive Vibration Suppression: Numerical Modeling With Experimental Verification

2003 ◽  
Author(s):  
Zhiwei Xu ◽  
Michael Yu Wang ◽  
Tianning Chen
Keyword(s):  
Vibration Suppression ◽  
Research Work ◽  
Numerical Procedure ◽  
Elastic Beam ◽  
Experimental Tests ◽  
Physical Models ◽  
Highly Nonlinear ◽  
Particle Damping ◽  
Frictional Forces ◽  
Damping Materials

As a simple and passive means, particle damping provides vibration suppression with granular particles embedded within their containing holes in a vibrating structure. Unlike in traditional damping materials, mechanisms of energy dissipation of particle damping are primarily related to friction and impact phenomena which are highly nonlinear. In the research work reported in the paper we investigate an elastic beam structure with drilled longitudinal holes filled with damping particles. Our focus is on the form of damping due to shear friction induced by strain gradient along the length of the structure. We present physical models to take into account of the shear frictional forces between particle layers and impacts of the particles with the containing holes. A numerical procedure is presented to predict the damping effect. Experimental tests of the beam for various different damping treatments are also conducted. Model predictions are validated by experimental results.

A Discrete Element Model for Brash Ice Simulations

2020 ◽  
Author(s):  
Jonas Behnen ◽  
Quentin Hisette ◽  
Sören Ehlers ◽  
Rüdiger U. Franz von Bock und Polach
Keyword(s):  
Numerical Simulation ◽  
Mechanical Behaviour ◽  
Experimental Tests ◽  
Element Model ◽  
Discrete Element ◽  
Friction Model ◽  
Physical Models ◽  
Physical Behaviour ◽  
Ice Conditions ◽  
Definition Of

Abstract Most merchant ships operating in the cold regions are not able to break ice themselves, they can only navigate in the broken ice, the so-called brash ice channels. Today’s standard requires a model test in real brash ice conditions to be carried out and realistic additional resistances to be estimated from this. The problem is that they can only be performed at the end of the design process. The possibility of changing the ship design within the development process can only be guaranteed by using a simulation tool, based on the Discrete Element Method. The problem with the development of this numerical simulation is the correctness of the mapping of the physical behaviour of brash ice. The physical models used are often simplified and not sufficient to represent the complex mechanical behaviour of brash ice. Thus, another problem with the use of numerical simulation is the selection of the correct parameters to describe the mechanical behaviour. A concrete definition of the used material parameters does not exist and the experimental tests for the determination of the physical properties are often complex and not standardized. This paper examines the mechanical behaviour of brash ice and the descriptive parameters of each ice rubble. On this basis, the physical behaviour in nature is compared with the model used in numerical simulation. As a result, physical inconsistencies are determined and new solution approaches are proposed, for example in the form of a new contact model, an extension of the friction model or a change of the descriptive particle shape.

Sign in / Sign up

Export Citation Format

Share Document