Adaptive finite volume discretization of density driven flows in porous media.
Adaptive modeling for free-surface flows
This work represents a first step towards the simulation of the motion of water in a complex hydrodynamic configuration, such as a channel network or a river delta, by means of a suitable “combination” of different mathematical models. In this framework a wide spectrum of space and time scales is involved due to the presence of physical phenomena of different nature. Ideally, moving from a hierarchy of hydrodynamic models, one should solve throughout the whole domain the most complex model (with...
Adaptive panel representation for 3D vortex ring motion and instability.
Adaptive step-size control in simulation of diffusive CVD processes.
Addendum to "The well-posedness of a swimming model in the 3-D incompressible fluid governed by the nonstationary Stokes equation"
In this addendum we address some unintentional omission in the description of the swimming model in our recent paper (Khapalov, 2013).
Addition au Mémoire sur la Théorie des ondes et des remous qui se propagent le long d'un canal rectangulaire, etc.
Additional note on partial regularity of weak solutions of the Navier-Stokes equations in the class
We present a simplified proof of a theorem proved recently concerning the number of singular points of weak solutions to the Navier-Stokes equations. If a weak solution belongs to , then the set of all possible singular points of in is at most finite at every time .
Adesione di membrane fluide
Adiabatic Evolution of Coupled Waves for a Schrödinger-Korteweg-de Vries System
The effective dynamics of interacting waves for coupled Schrödinger-Korteweg-de Vries equations over a slowly varying random bottom is rigorously studied. One motivation for studying such a system is better understanding the unidirectional motion of interacting surface and internal waves for a fluid system that is formed of two immiscible layers. It was shown recently by Craig-Guyenne-Sulem [1] that in the regime where the internal wave has a large...
Adiabatic Shearing of an Incompressible gas Caused by ΄΄Oscillatory΄΄ Inertial Force
Advancing analysis capabilities in ANSYS through solver technology.
Aerodynamic Computations Using a Finite Volume Method with an HLLC Numerical Flux Function
A finite volume method for the simulation of compressible aerodynamic flows is described. Stabilisation and shock capturing is achieved by the use of an HLLC consistent numerical flux function, with acoustic wave improvement. The method is implemented on an unstructured hybrid mesh in three dimensions. A solution of higher order accuracy is obtained by reconstruction, using an iteratively corrected least squares process, and by a new limiting procedure....
Aerodynamic deceleration at velocities near the escape velocity
This article presents basic procedures for calculating the trajectory of a spaceship that uses only the Earth’s atmosphere to reduce its speed, allowing it to land on the Earth’s surface successfully. The first flight of the ARTEMIS program, which took place from November 16 to December 11 2022, was used as a template for the calculations. All calculations are performed in the symbolic algebra program Maple. To simplify the calculations, forces that have a less significant impact on the shape of...
Air entrainment in transient flows in closed water pipes : A two-layer approach
In this paper, we first construct a model for free surface flows that takes into account the air entrainment by a system of four partial differential equations. We derive it by taking averaged values of gas and fluid velocities on the cross surface flow in the Euler equations (incompressible for the fluid and compressible for the gas). The obtained system is conditionally hyperbolic. Then, we propose a mathematical kinetic interpretation of this system to finally construct a two-layer kinetic scheme...
ALBERT---Software for scientific computations and applications.
Alcune osservazioni sulle onde magnetoacustiche
Nel presente lavoro si fanno alcune osservazioni sulle onde magnetoacustiche. Esse, per quanto è a conoscenza dell'autore, non sono presenti nella vastissima letteratura sull'argomento; nonostante la loro semplicità, è sembrato di un qualche interesse segnalarle esplicitamente per il loro contenuto fisico. Specificatamente riguardano: l'effetto Doppler; la quantità di moto; il carattere di onde di condensazione; il carattere conservativo del campo di forza magnetica; l'equipartizione dell'energia....
Algebraic foundation of some distribution algebras
All-at-once preconditioning in PDE-constrained optimization
The optimization of functions subject to partial differential equations (PDE) plays an important role in many areas of science and industry. In this paper we introduce the basic concepts of PDE-constrained optimization and show how the all-at-once approach will lead to linear systems in saddle point form. We will discuss implementation details and different boundary conditions. We then show how these system can be solved efficiently and discuss methods and preconditioners also in the case when bound...
Almost global solutions of the free boundary problem for the equations of a magnetohydrodynamic incompressible fluid
Almost global in time existence of solutions for equations describing the motion of a magnetohydrodynamic incompressible fluid in a domain bounded by a free surfaced is proved. In the exterior domain we have an electromagnetic field which is generated by some currents which are located on a fixed boundary. We prove that a solution exists for t ∈ (0,T), where T > 0 is large if the data are small.
Alternating Iteration and Elliptic Variational Inequalities.