Effects Of Coriolis Acceleration Research Articles

Research on Mechanism and Application of Coriolis Acceleration

Chongqing Bus falling into the river shocked the whole country. In order to find out whether the Coriolis illusion is one of the real causes of Chongqing Bus falling into the river, the mechanism of Coriolis acceleration is studied, and the corresponding analysis of the phenomenon caused by the Coriolis acceleration is carried out. The driver’s head in Chongqing Bus falling into the river is modelled and calculated. It is concluded that the effect of Coriolis acceleration can be ignored when the object’s motion speed is low, that is, the main cause of Chongqing Bus falling into the river is not Coriolis illusion.

Underlining possible effects of Coriolis acceleration in experiments with a Mössbauer source

In recent years it seems that, by measuring the transverse Doppler effect in experiments with a Mössbauer source, we observe a higher blue-shift compared to that provided by the standard relativistic time dilation. If this experimental measure will be officially recognized by the scientific community, we believe that the correct explanation must be sought within Einstein's General Relativity theory. Having this in mind, the aim of this paper is to suggest a possible interpretation of the experimental results. We immediately emphasize that ours is only an idea and does not claim to be certainly the correct explanation in the case in which the experimental data will be confirmed.

Instability and Convection in Rotating Porous Media: A Review

A review on instability and consequent natural convection in rotating porous media is presented. Taylor-Proudman columns and geostrophic flows exist in rotating porous media just the same as in pure fluids. The latter leads to a tendency towards two-dimensionality. Natural convection resulting from density gradients in a gravity field as well as natural convection induced by density gradients due to the centripetal acceleration are being considered. The former is the result of gravity-induced buoyancy, the latter is due to centripetally-induced buoyancy. The effect of Coriolis acceleration is also discussed. Linear stability analysis as well as weak nonlinear solutions are being derived and presented.

Global dynamics of fluid conveying nanotubes

In the present article, an effort is made to analyse the coupled global dynamics of nanoscale fluid-conveying tubes. The influences of geometric nonlinearity are captured through the nonlinear Euler–Bernoulli strain relation of beams. Moreover, the size influences related to the nanoscale tube are captured via developing a nonlocal strain gradient model of beams. The Beskok–Karniadakis theory is also used for capturing the size influences related to the nanofluid. In addition to size influences, Coriolis acceleration effects together with the influences of the centrifugal acceleration are taken into account. Hamilton's principle gives two coupled equations of motions, which are discretised utilising Galerkin's technique. A time integration scheme is used for extracting the global dynamic characteristics of the nanotube containing nanofluid flow. The non-dimensional critical speed associated with buckling is also determined. It is found that the nanofluid speed plays a crucial role in the global dynamics in both the subcritical and supercritical regimes.

Hydraulic Jump in the Gulf of California

Acoustic Doppler current profiles and water density profiles were measured over the 280 m deep continental slope of the Gulf of California to elucidate the bathymetric effect on zooplankton distribution. These measurements were combined with water velocity and density simulations from the Regional Ocean Model System with and without the influence of Coriolis acceleration. The data revealed an acceleration of the near-bottom flow as it moved toward increasing depths. This acceleration was produced by the adjustment of the isopycnals to bathymetry (hydraulic jump). Zooplankton patches moved downward at the continental slope and then upward, thus exhibiting wave patterns. Model outputs without the effect of Coriolis acceleration also suggested that vertical zooplankton concentration followed a wave pattern. However, when Coriolis acceleration was added to the momentum equation, the horizontal zooplankton distribution was enhanced, which reduced the vertical zooplankton concentration observed over irregular bathymetries. Coriolis acceleration was responsible for horizontal dispersal of up to 20% of the total zooplankton concentration located over the wave trough.

Coupling of In-Plane Flexural, Tangential, and Shear Wave Modes of a Curved Beam

In this paper, the coupling effects among three elastic wave modes, flexural, tangential, and radial shear, on the dynamics of a planar curved beam are assessed. Two sets of equations of motion governing the in-plane motion of a curved beam are derived, in a consistent manner, based on the theory of elasticity and Hamilton’s principle. The first set of equations retains all resulting linear coupling terms that includes both static and dynamic coupling among the three wave modes. In the derivation of the second set of equations, the effects of Coriolis acceleration and high-order elastic coupling terms are neglected, which leads to a set of equations without dynamic coupling terms between the tangential and shear wave modes. This second set of equations of motion is the one most commonly used in studies on thick curved beams that include the effects of centerline extensibility, rotary inertia, and shear deformation. The assessment is carried out by comparing the dynamic behavior predicted by each curved beam model in terms of the dispersion relations, frequency spectra, cutoff frequencies, natural frequencies and mode shapes, and frequency responses. In order to ensure the comparison is based on accurate results, the wave propagation technique is applied to obtain exact wave solutions. The results suggest that the contributions of the dynamic and high-order elastic coupling terms to the response of a thick curved beam are quite significant and that these coupling terms should not be neglected for an accurate analysis of a thick curved beam with a large curvature parameter.

Stability of Solutal Convection in a Rotating Mushy Layer Solidifying from a Vertical Surface

We consider the effects of rotation in a mushy layer being cast from a vertical surface where the effects of Coriolis acceleration, gravity and centrifugal effects are included. It is demonstrated that the Coriolis acceleration and gravity play a passive role in convection and are excluded from the stability criteria. The stability criteria is presented as the critical centrifugal Rayleigh numbers referenced for locations far away (start of solidification) and close to (nearing end of solidification) the axis or rotation.

Three-Dimensional Convection in an Inclined Porous Layer Heated from below and Subjected to Gravity and Coriolis Effects

The linear stability theory is used to investigate analytically the effects of Coriolis acceleration on gravity driven convection in a rotating porous layer. The stability of a basic solution is analysed with respect to the onset of stationary convection. It was discovered that increasing the Taylor number caused degeneracy to polyhedric cells for a specific range of inclination angles. The effects of the magnitude of the horizontal wavenumber is discussed in relation to the magnitude of the Taylor number.

Vibration analysis of spinning cylindrical shells by finite element method

The vibration of spinning cylindrical shells are analyzed by using nine-node super-parametric finite element with shear and axial deformation and rotatory inertia. The non-linear plant-shell theory for large deflection is used to handle the cylindrical shell before it reaches equilibrium state by centrifugal force. Hamilton principle is used to present the motion equation of finite element form. The effects of Coriolis acceleration, centrifugal force, initial tension and geometric non-linearity due to large deformation are considered in this model. The effect of geometric non-linearity of large deformation on the frequency of spinning cylindrical shells, the effect of boundary conditions on the frequency parameter of spinning cylindrical shells and the effect of rotation speed on the different modes of spinning cylindrical shells have been investigated in detail.

THE INFLUENCE OF ROTATION ON VIBRATION OF A THICK CYLINDRICAL SHELL

The problems of the vibration of rotating cylindrical shells are solved by using nine-node super-parametric finite element with shear and axial deformation and rotatory inertial. The non-linear plate-shell theory for large deflection is used to handle the cylindrical shell before it reaches equilibrium state by centrifugal force. The effects of Coriolis acceleration, centrifugal force, initial tension and geometric non-linearity due to large deformation are considered in this model. Eight categories of mode of a rotating thick cylindrical shell are presented. The effects of rotation on different three-dimensional modes of cylindrical shell are discussed in detail.

Effects of Coriolis Acceleration on the Forced Vibration of Rotating Cylindrical Shells

Effects of Coriolis Acceleration on the Forced Vibration of Rotating Cylindrical Shells

Natural frequencies of twisted rotating plates

A detailed comparison is presented of the predicted eigenfrequencies of twisted rotating plates as obtained by using two different shape functions. Primarily, rotating twisted plates of two different aspect ratios and two different thickness ratios are considered. The effects of rotation are included by using a “stress smoothing” technique when calculating the augmented stiffness matrix. In addition, the effects of Coriolis acceleration, contributions from membrane behaviour, setting angle and sweep angle are considered. The effects of geometric non-linearity are briefly discussed. Finally, results of a brief study of cambered plates are presented.

High Reynolds Number Turbulence Model of Rotating Shear Flows

A Reynolds stress closure model for rotating turbulent shear flows is developed. Special attention is paid to keeping the model constants independent of rotation. First, a general forms of the model of a Reynolds stress equation and a dissipation rate equation are derived, the only restrictions of which are high Reynolds number and incompressibility. The model equations are then applied to two-dimensional equilibrium boundary layers and the effects of Coriolis acceleration on turbulence structures are discussed. Comparisons with the experimental data and with previous results in other external force fields show that there exists a very close analogy among centrifugal buoyancy and Coriolis force fields. Finally, the model is applied to predict the two-dimensional boundary layers on rotating palane walls. Comparisons with existing data confirmed its capability of predicting mean- and turbulent quantites without employing any empirical relations in rotating fields.

A parametric study of vibration of rotating pre-twisted and tapered low aspect ratio cantilever plates

A finite element technique has been used to determine the natural frequencies of a pre-twisted and tapered plate mounted on the periphery of a rotating disc. The pre-twisted plate has been idealized as an assemblage of three noded triangular shell elements with six degrees of freedom at each node. In the analysis the initial stress effect (geometric stiffness) and other rotational effects except the Coriolis acceleration effect have been included. The eigenvalues have been extracted by using a simultaneous iteration technique. Computation of frequencies has been carried out for plates of aspect ratios 1 and 2. Other parameters considered are pre-twist, taper, skew angle and disc radius. From the results of computations an extension to the existing empirical formulae derived by Dokainiah and Rawtani [1] has been suggested for computing natural frequencies of rotating pre-twisted and tapered cantilever plates.

On the mathematics of data assimilation

The problem of convergence of a “forward-backward” assimilation is considered for the most general dynamical system. Using elementary techniques of stability theory, it is shown that the variation, over one assimilation cycle, of the difference between the assimilating model and the state to be reconstructed is, to the first order, determined by a perfectly defined amplification matrix. This leads to a straightforward criterion for convergence, depending on the eigenvalues of that matrix. This convergence criterion has in effect already been shown in a previous article to be verified by the linearized meteorological equations. It is shown here to be verified by the non-linear shallow-water equations, in the case of successive observations of the geopotential field, at least when these observations are sufficiently close in time. Numerical experiments support the theoretical results, and they together lead to the following description of the effects of an assimilation of geopotential observations. The divergent part of the wind field is reconstructed more rapidly, because it is directly influenced by introductions of observations. The rotational part is reconstructed indirectly and more slowly, mostly through the effect of Coriolis acceleration. These results are independent of whether or not the flow to be reconstructed is geostrophic, and do not require the presence of any dissipative process in the assimilating model. The effect of observing and/or modelling errors is considered, and small errors are shown not to modify the convergence properties of an assimilation. Finally, a theoretical method is defined through which the amplification matrix over one assimilation cycle can be made equal to zero, thereby optimizing the convergence of the process. DOI: 10.1111/j.2153-3490.1981.tb01755.x

Effects of System Rotation on the Performance of Two-Dimensional Diffusers

Experiments with incompressible flow are reported concerning the effects of Coriolis acceleration on flow separation and on separated flow in plane-wall diffusers of rectangular cross section. The diffusers were rotated about an axis perpendicular to the plane of the nearly two-dimensional flow in order to simulate some features of the blade-to-blade flow distribution in the radial portion of the centrifugal impeller. Various stall regimes are mapped on coordinates of rotation number and diffuser area ratio (at fixed wall length). Diffuser pressure-recovery coefficient is reported as a function of area ratio and rotation number. These data demonstrate that, by suppressing turbulent mixing and shear stress in the suction-side boundary layers, the Coriolis acceleration field greatly enhances the tendency for stall to appear in a diffuser. This effect causes a corresponding reduction in the throat-to-exit pressure recovery as compared to that of nonrotating diffusers of the same geometry and inlet flow blockage.

Effect of Coriolis acceleration on the vibrations of rotating disks

The changes effected by the Coriolis acceleration in the frequencies of inplane vibrations of a rotating disk are calculated. It is shown that the current practice to neglect this effect in everyday engineering calculations is quite justified. It is also shown that when disks are spun at ultra high speeds, say exceeding the one that corresponds with one-tenth of the lowest natural frequency of a stationary disk, the effect does become significant.

Vestibular problems in space travel.

A short survey is made of the vestibular problems related to space travel i.e. 1) linear acceleration, 2) weightlessness and 3) rotating space stations. Longer periods of weightlessness make it necessary to generate artificial gravitation by rotation. The effects of coriolis acceleration in rotating environment have been studied and methods to overcome this disturbing fenomenon outlined.

The Cauchy–Poisson problem for a rotating liquid

A semi-infinite body of liquid is in uniform rotation about a vertical axis for t < 0. A concentrated, vertical displacement of the free surface is imposed at t = 0. The motion of the free surface for t > 0 is calculated in linear approximation with the aid of Hankel and Laplace transformations, together with an intermediate transformation to parabolic co-ordinates. The result appears as an integral superposition of dispersive waves that divides naturally into two parts, corresponding to waves of the first and second class, with angular frequencies that are respectively greater or less than twice the angular speed of rotation. The waves of the first class, which are qualitatively similar to those in the classical (Cauchy–Poisson) problem, are found to dominate the asymptotic representation, as obtained through a stationary-phase approximation. The analysis is carried out in such a way as to separate the effects of Coriolis acceleration and free-surface curvature. Attention is focused on concave surfaces, such as would be realized in a laboratory experiment, but it is pointed out that striking differences exist between the dispersion laws for concave and convex surfaces, especially as regards waves of the second class.

Altitude Corrections for Coriolis and Other Accelerations

Some apology, or at least an adequate excuse, is needed for resurrecting a theoretical treatment of the effect of coriolis acceleration on observations of altitude made with a bubble sextant. Such an excuse is provided by the recent publication by Dr. J. J. Green of an article suggesting that the correction table (Z-correction) given in both the British and AmericanAir Almanacs(and in many other Air Almanacs) is incomplete. In a reasoned letter to the Editor ofNavigation, Dr. G. M. Clemence, Director of the American Nautical Almanac Office, has given a simple and straightforward explanation of the two separate and distinct causes for the deviation of the zenith as indicated by the bubble of a bubble sextant; and he has further justified the present practice adopted in the almanacs. Considerable interest has, however, been aroused and it seems opportune to give a previously unpublished general derivation of the theoretical correction, together with a brief discussion of the difficulties of practical application.