Numerische Methoden zur Berechnung von Druckverteilungen und zur Identifikation von Luftlagem

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Numerical comparison of hybridized discontinuous Galerkin and finite volume methods for incompressible flow

A numerical comparison of a hybridizable discontinuous Galerkin method proposed by Nguyen et al. and the well established finite volume method of second order in space represented by the icoFoam and simpleFoam solver of OpenFOAM is given. The hybridizable discontinuous Galerkin method has been reformulated as Picard iteration, hybridized and implemented from scratch. The methods are introduced and four numerical standard simulations are used in order to benchmark and evaluate the solver - the Taylor-Green vortex, the 180 degrees fence case as well as a two-dimensional stationary and non-stationary DFG benchmark. The numerical examples suggests hybridized discontinuous Galerkin methods are a competitive alternative to finite volume solvers for incompressible fluid simulations due to high accuracy and better stability properties

Analysis of optimal boundary control of the Boussinesq approximation

A revised version was published as Preprint 10-2008.In the present paper we complement the work in preprint 15-03 of the Inst. of Mathematics of the TU Berlin (also published in ZAMM 86(2006)6) with presenting the analytical framework for general optimal boundary control problems of the Boussinesq approximation. We prove existence of optimal controls, use results of H. Gajewski to prove existence and uniqueness of solutions to state and the adjoint system, and derive first order necessary as well as second order sufficient optimality conditions

Analysis of optimal boundary control of the Boussinesq approximation

This preprint is a revised version of Preprint 38-2007.In the present paper we complement a recent applied work with presenting the analytical framework for general optimal boundary control problems of the Boussinesq approximation. We prove existence of optimal controls, use results of Gajewski (1975) to prove existence and uniqueness of solutions to state and the adjoint system, and derive first order necessary as well as second order sufficient optimality conditions

A Multispecies Pedestrian Model based on a 3d multiphase incompressible fluid flow model

The idea to simulate pedestrian flow by the application of fluid dynamics equations has a certain history in that field. This approach is based on the application of partial differential equations, which makes it a macroscopic method. The need to simulate several different species of pedestrians is a need from the start, which has not been matched very well by numerical simulations of macroscopic type. The basis of the description of non dense pedestrian movement by incompressible fluid flow models consists in the introduction of an empty phase as a species of a multiphase system of distinct phases

The POD Dirichlet Boundary Control of the Navier-Stokes Equations: A Low-dimensional Approach to Optimal Control with High Smoothness

The proper orthogonal decomposition(POD) is an approach to capture a reduced order basis functions for a dynamical system. Utilizing the order reduction property of POD basis for minimizing computational cost to unsteady fluid flow control problem, we present a POD-based framework of the unsteady Dirichlet boundary control problem for Navier-Stokes equations. An extra basis function can be therefor constructed and appended into the general POD subspace, which as a key step enables the POD approach to the Dirichlet boundary control and results in the control problem merely in time scale. In the paper the excellent quality and flexibility of the POD approach to Dirichlet boundary flow control are confirmed numerically in several flow matching control examples

Some Fundamental Considerations for the Application of Macroscopic Models in the Field of Pedestrian Crowd Simulation

The means applied for the macroscopic modeling of pedestrian crowd simulations have originally been designed to model systems in the field of physics. This physics-mathematics coevolved toolbox makes certain assumptions about the nature of the objects that are dealt with. A natural question that arises now, is how well these tools fit pedestrian crowd simulations which deal with "systems'' of interacting intelligent "particles''. In this article we try to shed some light on these questions and try to outline a possible modeling approach

Fundamental Diagrams and Multiple Pedestrian Streams

The application of a fundamental diagram is one possible concept to base macroscopic models of pedestrian streams on. These diagrams have been derived for unidirectional pedestrian flows in restricted spatial settings like corridors and bottlenecks. In this paper we present some ideas to possibly extend this concept to cases of multi-directional fluxes on a plane, possibly with obstacles

Towards robust 3D face recognition from noisy range images with low resolution

For a number of different security and industrial applications, there is the need for reliable person identification methods. Among these methods, face recognition has a number of advantages such as being non-invasive and potentially covert. Since the device for data acquisition is a conventional camera, other advantages of a 2D face recognition system are its low data capture duration and its low cost. However, the recent introduction of fast and comparatively inexpensive time-of-flight (TOF) cameras for the recording of 2.5D range data calls for a closer look at 3D face recognition in this context. One major disadvantage, however, is the low quality of the data aquired with such cameras. In this paper, we introduce a robust 3D face recognition system based on such noisy range images with low resolution