Deterministic and Stochastic Prediction of the Hydrodynamics of a Three-Dimensional Body Falling Through Water

2008 ◽  
Author(s):  
Xuemei Zhu ◽  
Yuming Liu
Keyword(s):  
Deterministic Model ◽  
Three Dimensional ◽  
Field Measurements ◽  
The Body ◽  
Statistical Prediction ◽  
Viscous Drag ◽  
Physical Parameters ◽  
Practical Applications ◽  
Characteristic Features ◽  
Six Degree Of Freedom

We investigate the dynamics of a three-dimensional mine-shaped body falling through water deterministically and stochastically. A physics-based deterministic model, MINE6D, is developed for the prediction of the six degree-of-freedom motion of the body falling freely through water. In MINE6D, the hydrodynamic load due to the added inertia effect is obtained exactly by using a boundary-element method while the viscous drag associated with flow separation and vortex shedding is modeled using a quasi-steady approach. Since the mine motion is found to be highly sensitive to varying the physical parameters such as body geometry, mass distribution, and initial releasing conditions, we develop a stochastic model using Monte-Carlo MINE6D simulation for the statistical analysis of mine motions in practical applications. The statistical prediction is compared with available field measurements both qualitatively and quantitatively. The characteristic features and dependence on physical parameters of the statistical prediction of mine motions are investigated. The present study is of importance to the prediction of mine burial in seabed and the design of mines.

Vehicle Body and Roll Cage Assessment involving Frontal, Side and Roll-over Crash Analysis by FEA using LS-Dyna

2021 ◽  
Vol 13 (4) ◽  
Author(s):  
V. Hariram ◽  
K. Venkatesh ◽  
M. Venkata Saidev ◽  
M. Surisetty Mahesh ◽  
M. Vinothkumar ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Structural Steel ◽  
Three Dimensional ◽  
The Body ◽  
Vehicle Body ◽  
Crash Analysis ◽  
Steel Members ◽  
Vehicle Collision ◽  
Six Degree Of Freedom ◽  
Frontal Side

Simulating the vehicle collision has gained importance in the automotive sector due to its accuracy, cost effectiveness and enhanced reliability. It aids in improving the safety of driver and passenger and also examine the cause of crash or collision. This numerical analysis investigates the materials capability to enhance safety. A three-dimensional vehicle model was developed along with its roll cage using solid work tool. Hypermesh work bench was employed to discretise the sensitive parts of the body and roll cage using beam 189 element having six degree of freedom at each node. The existing structural steel members were replaced with reinforced carbon fibre in all the sensitive part of the body and roll cage and its structural stability was assessed using the frontal, side and roll over crash simulation using LS Dyna. This investigation also reveals the change in internal energy, kinetic energy absorption and momentum transfer for both structural steel and carbon fiber under all the crash scenarios. The outcomes of this numerical investigation proved that the reinforced carbon fiber can be effectively replaced with the structural steel to enhance safety.

Temperature profiles with respect to inhomogeneity and geometry of the human body

1988 ◽  
Vol 65 (3) ◽  
pp. 1110-1118 ◽  
Author(s):  
J. Werner ◽  
M. Buse
Keyword(s):  
Human Body ◽  
Three Dimensional ◽  
The Body ◽  
Physiological Data ◽  
Physical Parameters ◽  
Temperature Profiles ◽  
Metabolic Heat ◽  
Spatially Distributed ◽  
Adequate Representation ◽  
Neutral Conditions

Temperature profiles within the human body are highly dependent on the geometry and inhomogeneity of the body. Physical parameters such as density and heat conductivity of the various tissues and variables such as blood flow and metabolic heat production of different organs are spatially distributed and thereby influence the temperature profiles within the human body. Actual physiological knowledge allows one to take into account up to 54 different spatially distributed values for each parameter. An adequate representation of the anatomy of the body requires a spatial three-dimensional grid of at least 0.5-1.0 cm. This is achieved by photogrammetric treatment of three-dimensional anatomic models of the human body. As a first essential result, the simulation system has produced a realistic picture of the topography of temperatures under neutral conditions. Compatibility of reality and simulation was achieved solely on the basis of physical considerations and physiological data base. Therefore the simulation is suited to the extrapolation of temperature profiles that cannot be obtained experimentally.

scholarly journals TO THE THEORY OF n-DIMENSIONAL BRACHISTOCHRONE

2020 ◽  
pp. 53-60
Author(s):  
Gladkov S.O. ◽  
◽  
Bogdanova S.B. ◽  
Keyword(s):  
Three Dimensional ◽  
Plane Curve ◽  
Viscous Friction ◽  
Analytical Description ◽  
The Body ◽  
Viscous Drag ◽  
Friction Forces ◽  
Drag Forces ◽  
Moving Body ◽  
Plane Shape

In this paper, a solution to the problem of the motion of a brachistochrone in the ndimensional Euclidean space is firstly presented. The very first formulation of the problem in a two-dimensional case was proposed by J. Bernoulli in 1696. It represented an analytical description of the trajectory for the fastest rolling down under gravitational force only. Thereafter, a number of problems devoted to a brachistochrone were considered with account for gravitational forces, dry and viscous drag forces, and a possible variation in the mass of a moving body. Analytical solution to the formulated problem is presented in details by an example of the body moving along a brachistochrone in three-dimensional Cartesian coordinates. The obtained parametric solution is confirmed by a graphical interpretation of the calculated result. The formulated problem is solved for an ideal case when drag forces are neglected. If dry and viscous friction forces are taken into account, the plane shape of the brachistochrone remains the same,while the analysis of the solution becomes more complicated. When, for example, a side air flow is taken into account, the plane curve is replaced by a three-dimensional brachistochrone.

Application of the Joint Coordinate System to Three-Dimensional Joint Attitude and Movement Representation: A Standardization Proposal

1993 ◽  
Vol 115 (4A) ◽  
pp. 344-349 ◽  
Author(s):  
G. K. Cole ◽  
B. M. Nigg ◽  
J. L. Ronsky ◽  
M. R. Yeadon
Keyword(s):  
Coordinate System ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Distal Segment ◽  
The Body ◽  
Proximal Segment ◽  
Practical Applications ◽  
Flexion Extension ◽  
Joint Coordinate System ◽  
Selection Of

The selection of an appropriate and/or standardized method for representing 3-D joint attitude and motion is a topic of popular debate in the field of biomechanics. The joint coordinate system (JCS) is one method that has seen considerable use in the literature. The JCS consists of an axis fixed in the proximal segment, an axis fixed in the distal segment, and a “floating” axis. There has not been general agreement in the literature on how to select the body fixed axes of the JCS. The purpose of this paper is to propose a single definition of the body fixed axes of the JCS. The two most commonly used sets of body fixed axes are compared and the differences between them quantified. These differences are shown to be relevant in terms of practical applications of the JCS. Argumentation is provided to support a proposal for a standardized selection of body fixed axes of the JCS consisting of the axis eˆ1 embedded in the proximal segment and chosen to represent flexion-extension, the “floating” axis eˆ2 chosen to represent ad-abduction, and the axis eˆ3 embedded in the distal segment and chosen to represent axial rotation of that segment. The algorithms for the JCS are then documented using generalized terminology.

Galerkin Boundary Elements for a Computation of the Surface Tractions in Exterior Stokes Flows

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Jorge D'Elía ◽  
Laura Battaglia ◽  
Alberto Cardona ◽  
Mario Storti ◽  
Gustavo Ríos Rodríguez
Keyword(s):  
Body Force ◽  
Three Dimensional ◽  
Boundary Integral ◽  
The Body ◽  
Creeping Flow ◽  
Viscous Drag ◽  
Singular Behavior ◽  
Fredholm Type ◽  
Total Body ◽  
Weighting Procedures

In the computation of a three–dimensional steady creeping flow around a rigid body, the total body force and torque are well predicted using a boundary integral equation (BIE) with a single concentrated pair Stokeslet- Rotlet located at an interior point of the body. However, the distribution of surface tractions are seldom considered. Then, a completed indirect velocity BIE of Fredholm type and second-kind is employed for the computation of the pointwise tractions, and it is numerically solved by using either collocation or Galerkin weighting procedures over flat triangles. In the Galerkin case, a full numerical quadrature is proposed in order to handle the weak singularity of the tensor kernels, which is an extension for fluid engineering of a general framework (Taylor, 2003, “Accurate and Efficient Numerical Integration of Weakly Singulars Integrals in Galerkin EFIE Solutions,” IEEE Trans. on Antennas and Propag., 51(7), pp. 1630–1637). Several numerical simulations of steady creeping flow around closed bodies are presented, where results compare well with semianalytical and finite-element solutions, showing the ability of the method for obtaining the viscous drag and capturing the singular behavior of the surface tractions close to edges and corners. Also, deliberately intricate geometries are considered.

scholarly journals Selection of Co-Belonging Ceramic Fragments from Archaeological Excavations and Their Location in Vase Bodies from Theroremanent Magnetization

2019 ◽  
Author(s):  
Markos Ntoukakis ◽  
Apostolos Pantinakis ◽  
Antonios Vafidis ◽  
Theodoros Markopoulos
Keyword(s):  
Rotational Symmetry ◽  
Three Dimensional ◽  
Field Measurements ◽  
The Body ◽  
Firing Process ◽  
Secondary Process ◽  
Ceramic Surface ◽  
Time Requirements ◽  
Archaeological Excavations ◽  
Selection Of

Selection of co-belonging fragments from the numerous ceramic findings of an archaeological excavation remains a difficult process of questionable effectiveness, based exclusively on the experience and patience of the conservators. While the screening of the fragments is a central prerequisite and the most important stage of the process of vase reconstruction, established methods based on scientific criteria and guaranteed efficiency for the detection of co-belonging ceramic fragments suggested in the bibliography, do not exist. On the contrary, for methods dealing with the assembly of vases from co-belonging fragments, which is a secondary process that can be done more easily and effectively in an empirical way, there exist numerous studies based on fragment morphology. However, even these are also not implemented because of the time requirements, sheer volume and complexity of the proposed methods, in order for them to be applicable in practice. The proposed methods in this paper are based on thermoremanent magnetization (A/m), which is calculated from the weak magnetic field measurements by a fluxgate-sensor/magnet apparatus forming a three-dimensional orthogonal system. Experimental measurements from fragments of 6 vases show that the magnetization magnitude of co-belonging fragments display similar values, despite the magnetic anisotropy of the ceramic material, since these belong to vases that are made of the same clay and fired under the same conditions. This is the criterion for finding ceramic fragments of the same vase from archaeological excavations. The thermoremanent magnetism directionality of fragments, which is aligned along the geomagnetic field at the same place and time during the vase firing process, as it is configured by their rotational symmetry, defines the position of the fragments on the body of the 6 vases. The shape of the original vase can be reconstructed when only a few non adjacent fragments are available. The proposed measurement apparatus can be used for the construction of a useable portable magnetometer specialized for ceramic surface measurements to achieve the above objectives.

scholarly journals A Study on Intelligent GIS Installation System Based on Six-DOF Parallel Multi-axis Motion Control

2021 ◽  
Vol 2074 (1) ◽  
pp. 012066
Author(s):  
Ti Liu ◽  
Hongwei Mao ◽  
Dong Lei ◽  
Boming Li ◽  
Dahong Fu
Keyword(s):  
Motion Control ◽  
Power Transmission ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Positioning System ◽  
Practical Applications ◽  
Visual Positioning ◽  
Six Dof ◽  
Six Degree Of Freedom ◽  
Three Dimensional Space

Abstract Aiming at the connection of pipelines during the GIS installation process of power transmission and transformation projects, this subject designs and produces an intelligent GIS installation system based on 6-DOF parallel multi-axis motion control, which is applied to practical applications. The intelligent installation system can realize six independent motions and their combined motions in three-dimensional space. Relying on the multi-dimensional visual positioning system, through the six-degree-of-freedom parallel multi-axis motion control system, the precise docking during the installation of the precision GIS cavity can be realized.

scholarly journals Selection of Co-Belonging Ceramic Fragments from Archaeological Excavations and Their Location in Vase Bodies from Thermoremanent Magnetization

2019 ◽  
Vol 9 (16) ◽  
pp. 3310
Author(s):  
Ntoukakis ◽  
Pantinakis ◽  
Vafidis ◽  
Markopoulos
Keyword(s):  
Rotational Symmetry ◽  
Three Dimensional ◽  
Field Measurements ◽  
The Body ◽  
Firing Process ◽  
Secondary Process ◽  
Ceramic Surface ◽  
Thermoremanent Magnetization ◽  
Archaeological Excavations ◽  
Selection Of

: Selection of co-belonging fragments from the numerous ceramic findings of an archaeological excavation based exclusively on the experience and patience of the conservators remains a difficult process of questionable effectiveness. While the screening of the fragments is a central prerequisite and the most important stage of the process of vase reconstruction, established methods based on scientific criteria and guaranteed efficiency for the detection of co-belonging ceramic fragments suggested in the bibliography do not exist. On the contrary, for methods dealing with the assembly of vases from co-belonging fragments, which is a secondary process that can be done more easily and effectively in an empirical way, there exist numerous studies based on fragment morphology. However, even these are also not implemented because of the time requirements, sheer volume and complexity of the proposed methods, in order for them to be applicable in practice. The proposed methods in this paper are based on thermoremanent magnetization (A/m), which is calculated from the weak magnetic field measurements by a fluxgate-sensor/magnet apparatus forming a three-dimensional orthogonal system. Experimental measurements from fragments of six vases show that the magnetization magnitude of co-belonging fragments display similar values, despite the magnetic anisotropy of the ceramic material, since these belong to vases made of the same clay and fired under the same conditions. This is the criterion for finding ceramic fragments of the same vase from archaeological excavations. The thermoremanent magnetism directionality of fragments, which is aligned along the geomagnetic field at the same place and time during the vase firing process, as it is configured by their rotational symmetry, defines the position of the fragments on the body of the six vases. The shape of the original vase can be reconstructed when only a few non adjacent fragments are available. The proposed measurement apparatus can be used for the construction of a useable portable magnetometer specialized for ceramic surface measurements to achieve the above objectives.

scholarly journals Coincident disruptive coloration

2008 ◽  
Vol 364 (1516) ◽  
pp. 489-496 ◽  
Author(s):  
Innes C Cuthill ◽  
Aron Székely
Keyword(s):  
Field Experiments ◽  
Three Dimensional ◽  
The Body ◽  
Body Parts ◽  
Effective Mechanism ◽  
General Outline ◽  
Body Form ◽  
Disruptive Coloration ◽  
Characteristic Features ◽  
Colour Patterns

Even if an animal matches its surroundings perfectly in colour and texture, any mismatch between the spatial phase of its pattern and that of the background, or shadow created by its three-dimensional relief, is potentially revealing. Nevertheless, for camouflage to be fully broken, the shape must be recognizable. Disruptive coloration acts against object recognition by the use of high-contrast internal colour boundaries to break up shape and form. As well as the general outline, characteristic features such as eyes and limbs must also be concealed; this can be achieved by having the colour patterns on different, but adjacent, body parts aligned to match each other (i.e. in phase). Such ‘coincident disruptive coloration’ ensures that there is no phase disjunction where body parts meet, and causes different sections of the body to blend perceptually. We tested this theory using field experiments with predation by wild birds on artificial moth-like targets, whose wings and (edible pastry) bodies had colour patterns that were variously coincident or not. We also carried out an experiment with humans searching for analogous targets on a computer screen. Both experiments show that coincident disruptive coloration is an effective mechanism for concealing an otherwise revealing body form.

scholarly journals Three Dimensional Magnetohydrodynamic Stretched Flow of Cross Nanofluids

2020 ◽  
Vol 89 (1-4) ◽  
pp. 28-35
Author(s):  
Ashok Misra ◽  
Soumyendra Mishra ◽  
Abdul Kaffoor Abdul Hakeem ◽  
Manoj Kumar Nayak
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transverse Velocity ◽  
Three Dimensional ◽  
Viscous Drag ◽  
Integration Scheme ◽  
Solid Boundary ◽  
Physical Parameters ◽  
The Impact

The purpose of the present study is to analyze the flow, heat and mass transfer characteristics in the three dimensional magnetohydrodynamic stretched flow of Cross nanofluids. In the present study, Brownian movement, thermophoresis, thermal and solute convective boundary conditions are considered. With boundary layer approximation and self-similarity transformations, the non dimensional nonlinear governing equations are solved via shooting iteration technique together with 4th order Runge-Kutta integration scheme. The impact of developed physical parameters on velocity, temperature, concentration, surface viscous drag, heat and mass transfer rates has been examined via appropriate graphs and discussions. The numerical results indicate that uplift in the magnetic field strength and Weissenberg number diminishes the axial and transverse velocity fields. Further, the temperature ratio parameter brings about substantial improvement to the temperature and the related layer. The outcomes of the present study provide significant contribution to the controlled fluid motion and regulating the rate of heat transportation from the solid boundary into the boundary layer.

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