Forced Vibration of a Body on an Elastic Stratum

1957 ◽  
Vol 24 (1) ◽  
pp. 55-58
Author(s):  
G. B. Warburton
Keyword(s):  
Resonant Frequency ◽  
Surface Area ◽  
Forced Vibration ◽  
The Body ◽  
Constant Depth ◽  
Disturbing Force ◽  
Axis Of Symmetry ◽  
Experimental Values ◽  
Circular Base ◽  
Good Agreement

Abstract The paper considers the forced vibration of a body with a circular base resting on a homogeneous elastic stratum of infinite surface area and constant depth. The body is subjected to a vertical disturbing force along the axis of symmetry. After evaluating an integral given by Arnold, Bycroft, and Warburton, curves are given showing the dependence of the resonant frequency on three parameters. Good agreement is obtained between theoretical values of the resonant frequency and experimental values taken from the previous paper.

Stratified flow over a bounded obstacle in a channel of finite height

1981 ◽  
Vol 110 ◽  
pp. 161-170 ◽  
Author(s):  
G. S. Janowitz
Keyword(s):  
Steady State ◽  
Stratified Flow ◽  
Steady State Solution ◽  
The Body ◽  
State Solution ◽  
Oseen Equations ◽  
Finite Height ◽  
Experimental Values ◽  
Oseen Model ◽  
Good Agreement

The steady-state solution for the stratified flow over a bounded obstacle in a channel of finite height is obtained through the use of the inviscid unsteady Oseen equations; the body streamline encloses and is produced by a planar momentum sink. The calculations are compared with the experimental observations of Wei, Kao & Pao (1975) and Baines (1977). In a case where theoretical and experimental values match, good agreement was found. This suggests that the Oseen model with its columnar, wavelike and decaying solutions may provide a reasonable alternative to Long's model for subcritical flows.

Forced Vibrations of a Body on an Infinite Elastic Solid

1955 ◽  
Vol 22 (3) ◽  
pp. 391-400
Author(s):  
R. N. Arnold ◽  
G. N. Bycroft ◽  
G. B. Warburton
Keyword(s):  
Elastic Solid ◽  
Infinite Medium ◽  
Elastic Model ◽  
Constant Depth ◽  
Amplitude Response ◽  
Torsional Mode ◽  
Exciting Frequency ◽  
Modes Of Vibration ◽  
Circular Base ◽  
Good Agreement

Abstract The paper considers the forced vibration of a rigid body resting on a homogeneous elastic medium of infinite surface area and constant depth which may be finite or infinite. Four modes of vibration for a body with a circular base are investigated; (a) vertical translation, (b) torsion, (c) horizontal translation, (d) rocking. For a semi-infinite medium the amplitude response can be obtained for any mass in terms of known constants of the system and two fundamental functions f1 and f2, which depend only on the exciting frequency and the properties of the medium. Close approximations to these functions have been evaluated for each mode. Experiments on an elastic model are described, the results of which are in good agreement with theoretical prediction. The behavior of a stratum of infinite area is more complex since functions f1 and f2 also depend on stratum depth. These functions have been evaluated for the torsional mode only, experimental results being given for the other modes.

A mathematical model of body kinematics in swimming tadpoles

1993 ◽  
Vol 71 (2) ◽  
pp. 407-413 ◽  
Author(s):  
W. M. Oxner ◽  
J. Quinn ◽  
M. E. DeMont
Keyword(s):  
Mathematical Model ◽  
Resonant Frequency ◽  
The Body ◽  
Numerical Techniques ◽  
Cross Sectional ◽  
Finite Dimensional ◽  
Straight Line ◽  
Locomotor Muscles ◽  
Variable Moment ◽  
Good Agreement

A mathematical model is described that predicts the body kinematics of tadpoles swimming in a straight line at constant velocity. The model is a forced beam with a variable moment of inertia and cross-sectional area. The beam is free at both ends and forced cyclically at the position that corresponds to the base of the tail in a real animal. This forcing regime simulates the real contraction of locomotor muscles. Finite-dimensional numerical techniques were used to approximate the solution. The lowest predicted fundamental frequency of vibration should be the resonant frequency of vibration of the tadpole. The predicted resonant frequency and the observed swimming frequencies were in good agreement.

On the short cylindrical waves due to a body heaving on water. I

1971 ◽  
Vol 70 (2) ◽  
pp. 311-321 ◽  
Author(s):  
P. F. Rhodes-Robinson
Keyword(s):  
Free Surface ◽  
Potential Problem ◽  
Vertical Axis ◽  
Short Wave ◽  
The Body ◽  
Dimensional Problem ◽  
Constant Depth ◽  
Force Coefficient ◽  
Cylindrical Waves ◽  
Axis Of Symmetry

AbstractIn this paper we obtain the short-wave asymptotic value of the force coefficient for a heaving body partially immersed in the free surface of water which has finite constant depth. The body is required to intersect the free surface normally and have a vertical axis of symmetry. The motion of the water is thus axisymmetric with short outgoing cylindrical waves at a distance, and these must be calculated. For this we use a non-rigorous argument. The potential problem discussed is analogous to the two-dimensional problem afready investigated involving a heaving surface cylinder. Numerical values are obtained in the case of a half-immersed sphere in conclusion.

Empirical Equation for Estimating the Area of a Maxillary Edentulous Jaw

1973 ◽  
Vol 52 (4) ◽  
pp. 725-730
Author(s):  
Hamdi Mohammed ◽  
W.M. Johnston ◽  
W.J. O'Brien
Keyword(s):  
Regression Analysis ◽  
Surface Area ◽  
Correlation Coefficient ◽  
Empirical Equation ◽  
Experimental Values ◽  
Good Agreement ◽  
Edentulous Jaw

An empirical equation to calculate the surface area of the maxillary edentulous jaw was formulated. The values obtained by use of the equation were compared with the values determined by two methods of area measurements. Regression analysis and correlation coefficient computation showed good agreement between the calculated and the experimental values.

The use of Body Surface Index as a Better Clinical Health indicators Compare to Body Mass Index and Body Surface Area for Clinical Application

2018 ◽  
pp. 131-136
Author(s):  
Shirazu I. ◽  
Theophilus. A. Sackey ◽  
Elvis K. Tiburu ◽  
Mensah Y. B. ◽  
Forson A.
Keyword(s):  
Surface Area ◽  
Body Surface Area ◽  
Clinical Application ◽  
Body Surface ◽  
Body Height ◽  
Health Indicators ◽  
The Body ◽  
Body Parameters ◽  
The Relationship ◽  
Individual Body

The relationship between body height and body weight has been described by using various terms. Notable among them is the body mass index, body surface area, body shape index and body surface index. In clinical setting the first descriptive parameter is the BMI scale, which provides information about whether an individual body weight is proportionate to the body height. Since the development of BMI, two other body parameters have been developed in an attempt to determine the relationship between body height and weight. These are the body surface area (BSA) and body surface index (BSI). Generally, these body parameters are described as clinical health indicators that described how healthy an individual body response to the other internal organs. The aim of the study is to discuss the use of BSI as a better clinical health indicator for preclinical assessment of body-organ/tissue relationship. Hence organ health condition as against other body composition. In addition the study is `also to determine the best body parameter the best predict other parameters for clinical application. The model parameters are presented as; modeled height and weight; modelled BSI and BSA, BSI and BMI and modeled BSA and BMI. The models are presented as clinical application software for comfortable working process and designed as GUI and CAD for use in clinical application.

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

scholarly journals Calculating the optimal hematocrit under the constraint of constant cardiac power

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michal Sitina ◽  
Heiko Stark ◽  
Stefan Schuster
Keyword(s):  
Blood Flow ◽  
High Performance ◽  
Animal Species ◽  
Normal Values ◽  
Mechanical Load ◽  
The Body ◽  
Trade Off ◽  
Cardiac Power ◽  
Optimal Value ◽  
Good Agreement

AbstractIn humans and higher animals, a trade-off between sufficiently high erythrocyte concentrations to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. Optimal hematocrit theory has been successful in predicting hematocrit (HCT) values of about 0.3–0.5, in very good agreement with the normal values observed for humans and many animal species. However, according to those calculations, the optimal value should be independent of the mechanical load of the body. This is in contradiction to the exertional increase in HCT observed in some animals called natural blood dopers and to the illegal practice of blood boosting in high-performance sports. Here, we present a novel calculation to predict the optimal HCT value under the constraint of constant cardiac power and compare it to the optimal value obtained for constant driving pressure. We show that the optimal HCT under constant power ranges from 0.5 to 0.7, in agreement with observed values in natural blood dopers at exertion. We use this result to explain the tendency to better exertional performance at an increased HCT.

scholarly journals The Stationary Concentrated Vortex Model

Climate ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 39
Author(s):  
Oleg Onishchenko ◽  
Viktor Fedun ◽  
Wendell Horton ◽  
Oleg Pokhotelov ◽  
Natalia Astafieva ◽  
...  
Keyword(s):  
Vortex Structure ◽  
Radial Direction ◽  
Symmetry Axis ◽  
Outer Part ◽  
Vertical Direction ◽  
Axially Symmetric ◽  
New Model ◽  
Vortex Model ◽  
Axis Of Symmetry ◽  
Good Agreement

A new model of an axially-symmetric stationary concentrated vortex for an inviscid incompressible flow is presented as an exact solution of the Euler equations. In this new model, the vortex is exponentially localised, not only in the radial direction, but also in height. This new model of stationary concentrated vortex arises when the radial flow, which concentrates vorticity in a narrow column around the axis of symmetry, is balanced by vortex advection along the symmetry axis. Unlike previous models, vortex velocity, vorticity and pressure are characterised not only by a characteristic vortex radius, but also by a characteristic vortex height. The vortex structure in the radial direction has two distinct regions defined by the internal and external parts: in the inner part the vortex flow is directed upward, and in the outer part it is downward. The vortex structure in the vertical direction can be divided into the bottom and top regions. At the bottom of the vortex the flow is centripetal and at the top it is centrifugal. Furthermore, at the top of the vortex the previously ascending fluid starts to descend. It is shown that this new model of a vortex is in good agreement with the results of field observations of dust vortices in the Earth’s atmosphere.

Analysis of the First Order and Slowly Varying Motions of an Axisymmetric Floating Body in Bichromatic Waves

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
João Pessoa ◽  
Nuno Fonseca ◽  
C. Guedes Soares
Keyword(s):  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Floating Body ◽  
Drift Motion ◽  
First Order ◽  
Motion Responses ◽  
Simple Geometry ◽  
Good Agreement

The paper presents an experimental and numerical investigation on the motions of a floating body of simple geometry subjected to harmonic and biharmonic waves. The experiments were carried out in three different water depths representing shallow and deep water. The body is axisymmetric about the vertical axis, like a vertical cylinder with a rounded bottom, and it is kept in place with a soft mooring system. The experimental results include the first order motion responses, the steady drift motion offset in regular waves and the slowly varying motions due to second order interaction in biharmonic waves. The hydrodynamic problem is solved numerically with a second order boundary element method. The results show a good agreement of the numerical calculations with the experiments.

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