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A cell boundary–element method is developed to solve viscous fluid–structure interaction problems modelled by Navier–Stokes equations. This is achieved through a hybrid approach incorporating boundary–element and finite–element methods. In the proposed scheme, cell equations are generated using the principles of the boundary–element method with global equations derived following the procedures of the finite–element method. A primitive–variable formulation with an unstructured mesh requirement forms the basis of the hybrid approach which can be applied to both two– and three–dimensional problems. The validation of this numerical scheme of study involving analytical and numerical mathematical procedures is carried out using a number of well–documented flow solutions and the accuracy and robustness of the method are demonstrated in these examples.

In this paper we study the Navier Stokes flow on the two-dimensional torus S{sup 1} x S{sup 1} excited by the external force (k{sup 2} sin ky, 0) and find the long-time behavior for the flow starting from some states, where S{sup 1} = [ 0, 2{pi}](mod 2{pi}). Especially for the case k = 2, it follows from an analysis and computation that the Navier-Stokes flow with the initial state cos(mx + ny) or sin(mx + ny) will likely evolve through at most one step bifurcation to either a steady-state solution or a time-dependent periodic solution for any Reynolds number and integers m and n.

This investigation continues the development of an anti-diffusive volume of fluid method [1] by improving accuracy through the addition of an artificial diffusion term, with a negative diffusion coefficient, to the original advection equation describing the evolution of the fluid volume fraction. The advection and diffusion processes are split into a set of two partial differential equations (PDEs). The improved anti-diffusive Volume of Fluid (VOF) method is coupled with a two-fluid flow solver to predict free surface flows and illustrated by examples given in two-dimensional flows. The first numerical example is a solitary wave travelling in a tank. The second example is a plunging wave generated by flow over a submerged obstacle of prescribed shape on a horizontal floor. The computational results are validated against available experimental data.

Oil reservoir properties can vary over a wide range of length scales. Reservoir simulation of the fluid flow uses numerical grid blocks have typical lengths of hundreds of metres. We need to specify meaningful values to put into reservoir engineering calculations given the large number of heterogeneities that they have to encompass. This process of rescaling data results in the calculation of ‘effective’ or ‘pseudo’ rock properties. That is a property for use on the large scale incorporating the many heterogeneities measured on smaller scales. For single phase flow, a variety of techniques have been tried in the past. These range from very simple statistical estimates to detailed numerical simulation. Unfortunately, the simple estimates tend to be inaccurate in real applications and the numerical simulation can be computationally expensive if not impossible for very fine grid representations of the reservoir. Likewise, pseudorelative permeabilities are time consuming to generate and often inaccurate. Real-space renormalization is an alternative technique which has been found to be computationally efficient and accurate when applied to single-phase flow. This approach solves the problem regionally rather than trying to solve the whole problem in one simulation. The effective properties of small regions are first calculated and then placed on a coarse grid. The grid is further coarsened and the process repeated until a single effective property has been calculated. This has enabled calculation of effective permeability of extremely large grids to be performed, up to 540 million grid blocks in one application. This paper extends the renormalization technique to two-phase fluid flow and shows that the method is at least 100 times faster than conventional pseudoization techniques. We compare the results with high resolution numerical simulation and conventional pseudoization methods for three different permeability models. We show that renormalization is as accurate as the conventional methods when used to predict oil recovery from heterogeneous systems.

The following is an edited transcript of the recorded discussion sessions of the symposium, prepared by F J Fahy and approved by the contributors. For the convenience of readers, the format is not chronological, but grouped in relation to the presentations which are identified by the underlined name of the presenting author. Discussions and comments of a more general nature which were not specifically related to individual papers are presented at the end of this section.

Correction for ‘A power-flow analysis based on continuum dynamics’ by J.-T. Xing and W. G. Price (Proc. R. Soc. Lond. A 455 , 401–436. (doi: 10.1098/rspa.1999.0319)). The equations on p. 430 should read as follows.

The following reference was omitted: Salingaros, N. A. 1990 Lorentz-force and magnetic stress in force-free configurations. Appl. Phys. Lett . 56, 617-619.

Based on a functional analysis approach, time history effects are introduced into the representation of the fluid forces associated with offshore structures operating at shallow draft, shallow submergence and/or having a multihull construction, etc. A general linear theory is developed illustrating the pattern of behavior expected in the structure when performing a free decay motion or a forced motion excited by sinusoidal waves. It is shown that even in a simple one-degree-of-freedom mathematical model describing the behavior of an offshore structure, multiple natural frequencies and resonances may be exhibited in the responses. These features are examined and the investigation extended to assess the possibility of multiple parametric instabilities arising in the motions. For this purpose, the mathematical model is slightly modified to include a specific sinusoidal time-dependent term—as is common in a Mathieu type analysis—and conditions determined allowing motion instabilities to occur. This is confirmed by simple numerical examples.

A two-dimensional strip theory is applied to the hydrodynamic analysis of a drydock-like section consisting of a semisubmerged monohull with a trapped inner water region. To verify the theoretical approach used, results presented for a semisubmersible monohull and a semisubmerged drydock are compared with data derived from three dimensional analysis and from experiments.

The principal objectives of the SLPX (Superconducting Long-Pulse Experiment) are: (1) to demonstrate quasi-steady operation of 3 to 5 MA hydrogen and deuterium tokamak plasmas at high temperature and high thermal wall loading, and (2) to develop reliable operation of prototypical tokamak reactor magnetics systems featuring a toroidal assembly of high-field niobium-tin coils, and a system of pulsed niobium-titanium superconducting poloidal-field coils. This paper describes the status of the engineering design features of the SLPX, with emphasis on the magnetics systems. The toroidal-field coils have an aperture of 3.1 m × 4.8 m, and can operate with a maximum field at the conductor of 12 T. The superconducting poloidal field magnetics system consists of a pulsed NbTi central solenoid, and a set of d.c. NbTi equilibrium-field coils. The entire machine is enclosed in an outer vacuum container equipped with re-entrant ports that provide ambient access to the room-temperature plasma vessel.

This paper discusses the numerical evaluation of the characteristic Kelvin wavelike disturbance trailing downstream from a translating submerged source. Mathematically the function describing the wavelike disturbance is expressed as a single integral with infinite integration limits and a rapidly oscillatory integrand. Numerical integration of such integrals is both cumbersome and time-consuming. Attention is therefore focused on two complementary Neumann-series expansions which were originally derived by Bessho [1].2 Numerically stable algorithms are presented for the accurate and efficient evaluation of the two series representations. When used in combination with the Chebyshev expansions for the nonoscillatory near-field component which were recently obtained by Newman [2], the present algorithms provide an effective solution to the numerical difficulties associated with the evaluation of the Kelvin wave source potential.

In recent years several papers [Grad(9), Condiff and Dahler(5), Baronowski and Romatowski(2), Eringen(8), Allen and de Silva(i)] have been written dealing with the possibility of antisymmetric stress in a fluid and its relationship with the internal micro-structure of the fluid. In the classical fluid dynamics of the Navier–Stokes equations, the molecules of the fluid element are treated as material points devoid of any internal spin motion and the only type of angular motion that the macroscopic elements of the fluid possess is the usual vorticity ½ curl v, the velocity of the fluid being v. In the case of fluids whose molecules are not regarded as material points, but are treated as micro-structures having internal spin, the total angular velocity of a macroscopic volume element will be equal to the vector sum of spins of the micro-structures and the part due to the vorticity.

The linear differential equations governing the motion of a ship in a sinusoidal wave disturbance are derived from the principles of rigid body dynamics. Stability criteria are obtained when the linear differential equations have ( a) constant coefficients and ( b) periodic time-dependent coefficients that are needed to describe the ship in a following sinusoidal wave. The frequency of encounter between ship and wave is not necessarily zero.

During the past twenty-seven years much work has been done on the Mississippi River between Cairo and New Orleans, but comparatively little has been accomplished in the way of permanent improvement...

Pseudocysts are the most common nonfunctioning cystic adrenal lesions associated with symptoms. We have studied tissue from two patients with large adrenal pseudocysts in whom no antecedent cause could be documented. Immunohistochemical examination of these formaldehyde-fixed paraffin-embedded tissues with antibodies directed against the major proteins of the basement membrane (laminin and type IV collagen) revealed intense linear staining surrounding the cystic spaces and at the compressed adrenal cortical/pseudocyst interface. These findings lead us to conclude that these lesions are vascular in nature and, therefore, closely related to the previously recognized adrenal cysts of endothelial origin.

A series of calculations was performed to analyze the activation of the structure of the Princeton Reference Design D- T Fusion Power Reactor. The relevant isotope transmutation chains were solved numerically for 30 years' operation (3/4 load factor) at 5310 MW(t). Decay heat and activity curves versus time after shutdown were obtained for the reference stainless steel structure and for a vanadium alloy as an alternate. Afterheat appears not to pose a safety hazard because of the large blanket heat capacity; however, the large amount of cobalt-60 produced in the steel (2.82 x 10/sup 7/ curies) may make the ultimate disposal of that material difficult. Although the activation in the vanadium is comparable to that in the steel, the short half-lives of the radioisotopes (less than a year) greatly reduce the disposal problems. (auth)

A ship moving at constant forward speed in calm water creates waves on the free surface and a pressure field within the fluid. Based on a Neumann-Kelvin mathematical model, pressure signatures are calculated at arbitrary positions in the water when created by a Wigley parabolic hull form travelling in a constant density, infinitely deep seaway. At fixed forward speeds, the contributions and characteristics of the nearfield and far field components to the pressure field are examined when determined from an 'exact' Neumann-Kelvin formulation and a slender body numerical approximation. The influence of fluid stratification is illustrated through calculations of the far field pressure signatures associated with a Wigley hull travelling in a shallow water medium consisting of an idealised water-mud stratification. These results are derived using the slender body numerical approximation and this very idealised model may be considered representative of a ship travelling in a harbour or shallow channel approach to a port.

Sternomastoid tumor (SMT), as part of the spectrum of muscular torticollis, presents in infants as a discrete mass lesion in the neck, typically unassociated with neck torsion. We describe two patients who underwent fine needle aspiration (FNA) of their neck mass. The cytopathology of these aspirates was composed solely of a mixture of benign-appearing spindle cells and degenerating myofibers. Both infants showed a gradual disappearance of the mass without surgical intervention. We believe that FNA cytology is a diagnostic tool applicable to neonates. Additionally, in the proper clinical setting, aspiration cytology can be diagnostic of the clinicopathologic entity of SMT.

Pseudocysts are the most common nonfunctioning cystic adrenal lesions associated with symptoms. We have studied tissue from two patients with large adrenal pseudocysts in whom no antecedent cause could be documented. Immunohistochemical examination of these formaldehyde-fixed paraffin-embedded tissues with antibodies directed against the major proteins of the basement membrane (laminin and type IV collagen) revealed intense linear staining surrounding the cystic spaces and at the compressed adrenal cortical/pseudocyst interface. These findings lead us to conclude that these lesions are vascular in nature and, therefore, closely related to the previously recognized adrenal cysts of endothelial origin.

Fundamentals of Infrared Technology By Marvin R. Holter, Sol Nudelman, Gwynn H. Suits, William L. Wolfe and George J. Zissis. (Macmillan Monographs in Applied Optics.) Pp. xv + 442. (New York and London: The Macmillan Company, New York, 1962.) 79s. Theory and Applications of Ultraviolet Spectroscopy By Prof. H. H. Jaffe and Prof. Milton Orchin. Pp. xv + 624. (New York and London: John Wiley and Sons, Inc., 1962.) 113s. Standardization of Spectrophotometric Data in the Near Ultraviolet, Visual and Near Infrared By Dr. Jorgen Fog. (Institute for Medical Biochemistry and Physiology, University of Oslo.) Pp. 64. (Oslo: Johan Grundt Tanum Forlag, 1962.) n.p.

The extensive analysis carried out in last years on nonlinear rolling motion of ships allowed to discover some very peculiar features of this motion. As a results, terms as subharmonic, bifurcation, jump in amplitude, symmetry breaking, deterministic chaos, non deterministic, non Gaussian and even fractals start appearing with increasing frequency in the literature. At the same time, their exact meaning and importance in the context of ship seakindliness and safety from capsizing and of the behaviour of floating structures at sea, is circulating among restricted areas of researchers in the field. In this paper the author, while presenting preliminary results relative to the possibility of bifurcations in a narrow band stochastic sea, tries to draw some conclusion about the relevance of the above phenomena from what could be called “the point of view of the Naval Architect”.