Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.16
of Telecommunication, and Global, Kyiv Information Space
This work is dedicated to the modeling methodology of a viscous fluid flows with the lattice Boltzmann method on graphic processors based on the technology of images rendering in web browsers WebGL. A two-dimensional nine-velocity LBM model (D2Q9) with a collision integral in a Bhatnagar-Gross-Kruk approximation form is shown. The possibilities of calculation acceleration using WebGL technology is described, namely features of using textures to contain values of some physical quantities in numerical algorithms and using fremebuffers to storage the textures, influence of the texture parameters on the numerical algorithms, features of shaders programming. The questions of shader programs using for carrying out stages of physical modeling were considered. The proposed methodology was used to develop an original web program for modeling of classical test problems. Simulations of the Poiseuille flow in a plane channel and the flow around a circular cylinder in a plane channel were performed. The obtained results were compared with the results of calculations performed in the original verified modeling program based on the lattice Boltzmann method and in the Comsol Multiphysics package with the finite element method. Comparisons of the values of the velocity magnitude showed the consistency of the obtained results with the data of other numerical experiments. The analysis of computational speed in comparison with modeling using the optimized algorithm of a method with use of the technology of parallel calculations on CPU OpenMP in the original program is carried out. It is shown that the acceleration of calculations depends on the number of cells of the calculation grid. The results of the fluid flow modeling around a circular cylinder at Re = 1000 are demonstrated, which are obtained 30 times faster than with the calculations obtained with optimized lattice Boltzmann method and OpenMP technology.
{"title":"VISCOUS FLUID FLOW MODELING WITH THE LATTICE BOLTZMANN METHOD ON GRAPHICS PROCESSORS USING WebGL API","authors":"of Telecommunication, and Global, Kyiv Information Space","doi":"10.17721/2706-9699.2021.1.16","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.16","url":null,"abstract":"This work is dedicated to the modeling methodology of a viscous fluid flows with the lattice Boltzmann method on graphic processors based on the technology of images rendering in web browsers WebGL. A two-dimensional nine-velocity LBM model (D2Q9) with a collision integral in a Bhatnagar-Gross-Kruk approximation form is shown. The possibilities of calculation acceleration using WebGL technology is described, namely features of using textures to contain values of some physical quantities in numerical algorithms and using fremebuffers to storage the textures, influence of the texture parameters on the numerical algorithms, features of shaders programming. The questions of shader programs using for carrying out stages of physical modeling were considered. The proposed methodology was used to develop an original web program for modeling of classical test problems. Simulations of the Poiseuille flow in a plane channel and the flow around a circular cylinder in a plane channel were performed. The obtained results were compared with the results of calculations performed in the original verified modeling program based on the lattice Boltzmann method and in the Comsol Multiphysics package with the finite element method. Comparisons of the values of the velocity magnitude showed the consistency of the obtained results with the data of other numerical experiments. The analysis of computational speed in comparison with modeling using the optimized algorithm of a method with use of the technology of parallel calculations on CPU OpenMP in the original program is carried out. It is shown that the acceleration of calculations depends on the number of cells of the calculation grid. The results of the fluid flow modeling around a circular cylinder at Re = 1000 are demonstrated, which are obtained 30 times faster than with the calculations obtained with optimized lattice Boltzmann method and OpenMP technology.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"10 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85864445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.07
G. Voropaiev, O. Baskova
Despite the seeming simplicity of the steady flow in a pipe of constant radius, the question of the cause and process of the transition remains debatable. Especially since the necessary condition for the stability loss of parabolic profile is not satisfied, and the linear theory of hydrodynamic stability for an axisymmetric Poiseuille flow does not give growing axisymmetric eigen solutions for any Reynolds numbers, since the terms characterizing the interaction of disturbances with the initial velocity profile drop out in the linearized equations of momentum conservation. The report presents the results of the study of stages of convective stability loss for the flow at the initial section of the pipe depending on the variable parameters based on the numerical solution of the three-dimensional system of unsteady Navier-Stokes equations and the equation energy transfer. The variable parameters in this study were: Reynolds number, magnitude and gradient sign of the dynamic viscosity coefficient arising in nonisothermal flows. An analogy of the arising secondary axisymmetric large-scale toroidal vortex structures in the near-wall region to Tollmien-Schlichting waves in the region of the transition of the laminar boundary layer on the plate is shown. The subsequent loss of axisymmetry and stability of these torus-like vortex structures is analyzed, which leads to the formation of fairly regular longitudinal vortex structures downstream, the nonlinear interaction of which leads to chaotization of the flow. The lengths of these sections are determined depending on the Reynolds number, the magnitude and sign of the gradient of the dynamic viscosity coefficient.
{"title":"SOME FEATURES OF A LAMINAR FLOW STABILITY LOSS IN A PIPE","authors":"G. Voropaiev, O. Baskova","doi":"10.17721/2706-9699.2021.1.07","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.07","url":null,"abstract":"Despite the seeming simplicity of the steady flow in a pipe of constant radius, the question of the cause and process of the transition remains debatable. Especially since the necessary condition for the stability loss of parabolic profile is not satisfied, and the linear theory of hydrodynamic stability for an axisymmetric Poiseuille flow does not give growing axisymmetric eigen solutions for any Reynolds numbers, since the terms characterizing the interaction of disturbances with the initial velocity profile drop out in the linearized equations of momentum conservation. The report presents the results of the study of stages of convective stability loss for the flow at the initial section of the pipe depending on the variable parameters based on the numerical solution of the three-dimensional system of unsteady Navier-Stokes equations and the equation energy transfer. The variable parameters in this study were: Reynolds number, magnitude and gradient sign of the dynamic viscosity coefficient arising in nonisothermal flows. An analogy of the arising secondary axisymmetric large-scale toroidal vortex structures in the near-wall region to Tollmien-Schlichting waves in the region of the transition of the laminar boundary layer on the plate is shown. The subsequent loss of axisymmetry and stability of these torus-like vortex structures is analyzed, which leads to the formation of fairly regular longitudinal vortex structures downstream, the nonlinear interaction of which leads to chaotization of the flow. The lengths of these sections are determined depending on the Reynolds number, the magnitude and sign of the gradient of the dynamic viscosity coefficient.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"18 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81762228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.28
A. V. Shekhovtsov
For the case of modeling in the nonlinear ideal formulation of oscillations of an infinitely thin profile of the wing-propulsion, three components of the thrust force coefficient were distinguished - inertial, circulating, and vortex. The contribution to the traction force of each of the obtained components is investigated and the mechanisms of wing traction force formation at different types of oscillations are explained. It is revealed that the inertial-circulating principle underlies the work of the wing-propulsion. The inductive effect of the vortex trail on the traction force is small and negative.
{"title":"INERTIAL-CIRCULATING PRINCIPLE OF SWIMMING AND FLIGHT OF HYDRO- AND AEROBIONTS. PART 2","authors":"A. V. Shekhovtsov","doi":"10.17721/2706-9699.2021.1.28","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.28","url":null,"abstract":"For the case of modeling in the nonlinear ideal formulation of oscillations of an infinitely thin profile of the wing-propulsion, three components of the thrust force coefficient were distinguished - inertial, circulating, and vortex. The contribution to the traction force of each of the obtained components is investigated and the mechanisms of wing traction force formation at different types of oscillations are explained. It is revealed that the inertial-circulating principle underlies the work of the wing-propulsion. The inductive effect of the vortex trail on the traction force is small and negative.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"76 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85905447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.17
V. Dushkin, V. Melnik
A mathematical model of diffraction of E-polarized and H-polarized waves on a finite system of not perfectly conducting tapes is obtained. The value of the surface impedance on the two sides of the stripes is different. The initial boundary value problem for the Helmholtz equation with boundary conditions of the third kind was reduced to a system of boundary integral equations. This system of boundary integral equations consists of singular integral equations of the first kind and integral equations of the second kind with a logarithmic singularity. The method of parametric representation of integral operator was used to perform transformations. The values of the physical characteristics of the process are expressed through the solutions of the obtained systems of integral equations. Numerical solution of these equations is performed using a computational scheme based on the discrete singularities method.
{"title":"MATHEMATICAL MODEL OF WAVE DIFFRACTION BY THE SYSTEM OF STRIPES WITH DIFFERENT VALUES OF SURFACE IMPEDANCE","authors":"V. Dushkin, V. Melnik","doi":"10.17721/2706-9699.2021.1.17","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.17","url":null,"abstract":"A mathematical model of diffraction of E-polarized and H-polarized waves on a finite system of not perfectly conducting tapes is obtained. The value of the surface impedance on the two sides of the stripes is different. The initial boundary value problem for the Helmholtz equation with boundary conditions of the third kind was reduced to a system of boundary integral equations. This system of boundary integral equations consists of singular integral equations of the first kind and integral equations of the second kind with a logarithmic singularity. The method of parametric representation of integral operator was used to perform transformations. The values of the physical characteristics of the process are expressed through the solutions of the obtained systems of integral equations. Numerical solution of these equations is performed using a computational scheme based on the discrete singularities method.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"16 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89536447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.11
hydromechanics Nas Ukraine, 1 Інститут, гідромеханіки Нан України, Україна Київ
The results of experimental studies are presented in order to study the features of the formation of separated and vortex flows in the vicinity of a transversely streamlined cylinder on the surface of a hydraulically smooth rigid surface and to determine the space-time characteristics of sources of wall pressure fluctuations. The studies were carried out in laboratory conditions on transversely streamlined cylinders, which were located on a rigid surface. The field of wall pressure fluctuations was measured by a group of miniature piezoceramic pressure fluctuation sensors, which were installed flush with the streamlined rigid surface in front of the cylinder and in its wake. The research results were processed and analyzed using the mathematical apparatus of the theory of probability and mathematical statistics. The spectral and correlation characteristics of the separated flow in the vicinity of a transversely streamlined cylinder are obtained.
{"title":"TRANSVERSELY STREAMLINED CYLINDER ON RIGID SURFACE","authors":"hydromechanics Nas Ukraine, 1 Інститут, гідромеханіки Нан України, Україна Київ","doi":"10.17721/2706-9699.2021.1.11","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.11","url":null,"abstract":"The results of experimental studies are presented in order to study the features of the formation of separated and vortex flows in the vicinity of a transversely streamlined cylinder on the surface of a hydraulically smooth rigid surface and to determine the space-time characteristics of sources of wall pressure fluctuations. The studies were carried out in laboratory conditions on transversely streamlined cylinders, which were located on a rigid surface. The field of wall pressure fluctuations was measured by a group of miniature piezoceramic pressure fluctuation sensors, which were installed flush with the streamlined rigid surface in front of the cylinder and in its wake. The research results were processed and analyzed using the mathematical apparatus of the theory of probability and mathematical statistics. The spectral and correlation characteristics of the separated flow in the vicinity of a transversely streamlined cylinder are obtained.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"42 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88100003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.2.01
V. Grinchenko, V. Husak, V. T. Matsypura
The paper considers the use of two options of conjugation of wave fields in the method of partial domains: the first is the conjugation of wave fields in the sense of the root mean square approximation, the second is the pointwise conjugation of wave fields. A solution is obtained for the problem of radiation from one or two flat pistons into a wedge-shaped waveguide. It is shown that with the same number of modes in partial domains, the version of the root mean square approximation is more accurate. A quite acceptable calculation accuracy was obtained for the option of pointwise conjugation of fields at a certain value of the wave distance between the nodal points.
{"title":"USING TWO OPTIONS FOR CONJUGATING WAVE FIELDS IN THE METHOD OF PARTIAL DOMAINS","authors":"V. Grinchenko, V. Husak, V. T. Matsypura","doi":"10.17721/2706-9699.2021.2.01","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.2.01","url":null,"abstract":"The paper considers the use of two options of conjugation of wave fields in the method of partial domains: the first is the conjugation of wave fields in the sense of the root mean square approximation, the second is the pointwise conjugation of wave fields. A solution is obtained for the problem of radiation from one or two flat pistons into a wedge-shaped waveguide. It is shown that with the same number of modes in partial domains, the version of the root mean square approximation is more accurate. A quite acceptable calculation accuracy was obtained for the option of pointwise conjugation of fields at a certain value of the wave distance between the nodal points.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"1 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91132896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.2.06
M. Savkina
At the paper a linear regression model whose function has the form $f(x) = ax + b$, $a$ and $b$ — unknown parameters, is studied. Approximate values (observations) of functions $f(x)$ are registered at equidistant points $x_0$, $x_1$,..., $x_n$ of a line segment. It is also assumed that the covariance matrix of deviations is the Toeplitz matrix. Among all Toeplitz matrices, a family of matrices is selected for which all diagonals parallel to the main, starting from the (k +1)-th, are zero, $k = n/2$, $n$ — even. Elements of the main diagonal are denoted by $λ$, elements of the k-th diagonal are denoted by $c$, elements of the j-th diagonal are denoted by $c_{k−j}$ , $j = 1, 2,..., k − 1$. The theorem proved at the paper states that if $c_j = (k/(k + 1))^j c$, $j = 1, 2,..., k−1$, that the LS estimation and the Aitken estimation of the $a$ parameter of this model coincide for any values $λ$ and $c$, which provide the positive definiteness of the resulting matrix.
{"title":"EQUALITY OF LS AND AITKEN ESTIMATIONS OF THE HIGHER COEFFICIENT OF THE LINEAR REGRESSION MODEL IN THE CASE OF CORRELATED DEVIATIONS","authors":"M. Savkina","doi":"10.17721/2706-9699.2021.2.06","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.2.06","url":null,"abstract":"At the paper a linear regression model whose function has the form $f(x) = ax + b$, $a$ and $b$ — unknown parameters, is studied. Approximate values (observations) of functions $f(x)$ are registered at equidistant points $x_0$, $x_1$,..., $x_n$ of a line segment. It is also assumed that the covariance matrix of deviations is the Toeplitz matrix. Among all Toeplitz matrices, a family of matrices is selected for which all diagonals parallel to the main, starting from the (k +1)-th, are zero, $k = n/2$, $n$ — even. Elements of the main diagonal are denoted by $λ$, elements of the k-th diagonal are denoted by $c$, elements of the j-th diagonal are denoted by $c_{k−j}$ , $j = 1, 2,..., k − 1$. The theorem proved at the paper states that if $c_j = (k/(k + 1))^j c$, $j = 1, 2,..., k−1$, that the LS estimation and the Aitken estimation of the $a$ parameter of this model coincide for any values $λ$ and $c$, which provide the positive definiteness of the resulting matrix.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"123 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86634324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.18
G. Zrazhevsky, V. Zrazhevska
This work focuses on development of a mathematical apparatus that allows to perform an approximate description of inhomogeneities of finite sizes in a continuous bodies by arranging the sources given on sets of smaller dimensions. The structure and properties of source densities determine the adequacy of the model. The theory of differential forms and generalized functions underlies this study. The boundary value problems with nonsmooth coefficients are formulated. The solutions of such problems is sought in the form of weakly convergent series and as an alternative - an equivalent recurrent set of boundary value problems with jumps. A feature of this approach is the ability to consistently improve the adequacy of the description of inhomogeneity. This is important because it allows to qualitatively assess the impact of real characteristic properties on the accuracy of the model description. Reducing the dimensions of inhomogeneities allows the use of efficient methods such as the Green's function and boundary integral equations to obtain a semi-analytic solution for direct and inverse problems. The work is based on a number of partial problems that demonstrate the proposed approach in modeling of inhomogeneities. The problems of modeling of the set of finite defects in an oscillating elastic beam, the set of inhomogeneities of an arbitrary shape in an oscillating plate, fragile cracks in a two-dimensional elastic body under static loading are considered.
{"title":"MODELING OF FINITE INHOMOGENEITIES BY DISCRET SINGULARITIES","authors":"G. Zrazhevsky, V. Zrazhevska","doi":"10.17721/2706-9699.2021.1.18","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.18","url":null,"abstract":"This work focuses on development of a mathematical apparatus that allows to perform an approximate description of inhomogeneities of finite sizes in a continuous bodies by arranging the sources given on sets of smaller dimensions. The structure and properties of source densities determine the adequacy of the model. The theory of differential forms and generalized functions underlies this study. The boundary value problems with nonsmooth coefficients are formulated. The solutions of such problems is sought in the form of weakly convergent series and as an alternative - an equivalent recurrent set of boundary value problems with jumps. A feature of this approach is the ability to consistently improve the adequacy of the description of inhomogeneity. This is important because it allows to qualitatively assess the impact of real characteristic properties on the accuracy of the model description. Reducing the dimensions of inhomogeneities allows the use of efficient methods such as the Green's function and boundary integral equations to obtain a semi-analytic solution for direct and inverse problems. The work is based on a number of partial problems that demonstrate the proposed approach in modeling of inhomogeneities. The problems of modeling of the set of finite defects in an oscillating elastic beam, the set of inhomogeneities of an arbitrary shape in an oscillating plate, fragile cracks in a two-dimensional elastic body under static loading are considered.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"24 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72655710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.24
A. G. Rudnitskii, M. Rudnytska, L. Tkachenko
The paper considers a new method of separating respiratory sounds from heart sounds in a general signal registered on the surface of the human body. The proposed approach is based on a combination of Bayesian noise suppression techniques and methods of mathematical morphology. The proposed method was tested on real auscultatory signals. Evaluation of the efficiency of the algorithm using auditory, visual and numerical analysis shows that the developed approach is a promising alternative to existing techniques for separating auscultatory signals into its natural components.
{"title":"SINGLE-CHANNEL PROCESSING OF AUSCULTATORY SIGNALS USING METHODS OF MATHEMATICAL MORPHOLOGY","authors":"A. G. Rudnitskii, M. Rudnytska, L. Tkachenko","doi":"10.17721/2706-9699.2021.1.24","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.24","url":null,"abstract":"The paper considers a new method of separating respiratory sounds from heart sounds in a general signal registered on the surface of the human body. The proposed approach is based on a combination of Bayesian noise suppression techniques and methods of mathematical morphology. The proposed method was tested on real auscultatory signals. Evaluation of the efficiency of the algorithm using auditory, visual and numerical analysis shows that the developed approach is a promising alternative to existing techniques for separating auscultatory signals into its natural components.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"10 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72584577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17721/2706-9699.2021.1.27
A. V. Shekhovtsov
For the case of modeling in the nonlinear ideal formulation of oscillations of an infinitely thin profile of the wing-propulsion, three components of the thrust force coefficient were distinguished - inertial, circulating, and vortex. The contribution to the traction force of each of the obtained components is investigated and the mechanisms of wing traction force formation at different types of oscillations are explained. It is revealed that the inertial-circulating principle underlies the work of the wing-propulsion. The inductive effect of the vortex trail on the traction force is small and negative.
{"title":"INERTIAL-CIRCULATING PRINCIPLE OF SWIMMING AND FLIGHT OF HYDRO- AND AEROBIONTS. PART 1","authors":"A. V. Shekhovtsov","doi":"10.17721/2706-9699.2021.1.27","DOIUrl":"https://doi.org/10.17721/2706-9699.2021.1.27","url":null,"abstract":"For the case of modeling in the nonlinear ideal formulation of oscillations of an infinitely thin profile of the wing-propulsion, three components of the thrust force coefficient were distinguished - inertial, circulating, and vortex. The contribution to the traction force of each of the obtained components is investigated and the mechanisms of wing traction force formation at different types of oscillations are explained. It is revealed that the inertial-circulating principle underlies the work of the wing-propulsion. The inductive effect of the vortex trail on the traction force is small and negative.","PeriodicalId":40347,"journal":{"name":"Journal of Numerical and Applied Mathematics","volume":"100 1","pages":""},"PeriodicalIF":0.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73534828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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