Aksel, Mehmet Haluk
Finite elements are used to simulate the frontogenesis in a three-dimensional model employing sigma-coordinates. The basic flow is an east-west shear layer in which the velocity increases linearly with altitude and a periodic east-west perturbation is imposed on all variables. The effects of the element order, resolution, the boundary conditions, and time advance technique on the simulation of frontal development are examined. The space discretization is achieved by the first-order and the second-order isoparametric elements and the leapfrog time integration scheme is used. A satisfactory solution is produced, even if the front is entirely between the nodes. Because the stability of the time-dependent finite element solution depends extensively on the boundary conditions, the causes of instability are examined with respect to the boundary conditions. It is concluded that finite difference techniques are at present better than finite element techniques for most meteorological problems. The situation could change if the coupling of the boundary nodes could be used to improve the numerical stability to small perturbations.


A verification approach for dynamics of metamodel based conceptual models of the mission space
Eryılmaz, Utkan; Bilgen, Semih; Department of Information Systems (2011)
Conceptual models were introduced in the simulation world in order to describe the problem domain in detail before any implementation is attempted. One of the recent approaches for conceptual modeling of the military mission space is the KAMA approach which provides a process description, a UML based notation, and a supporting tool for developing conceptual models. The prominence of the approach stems from availability of guidance and applications in real life case studies. Although the credibility of a con...
A Modified Inverse Eigensensitivity Method for Large Finite Element Models
Unlu, Dogus; Ciğeroğlu, Ender; Özgen, Gökhan Osman (2016-01-28)
Finite element models should represent the dynamic behavior of real structures accurately to be subsequently used in design purposes. Therefore, finite element model updating methods have been developed in order to decrease the difference between analytical model and modal test results. In this paper, inverse eigensensitivity method as a sensitivity-based model updating method is summarized. Inverse eigensensitivity method with improved sensitivity computation which decreases the total calculation time of t...
A micro macro approach to rubber like materials Part II The micro sphere model of finite rubber viscoelasticity
Christian, Miehe; Göktepe, Serdar (Elsevier BV, 2005-10-01)
A micromechanically based non-affine network model for finite rubber elasticity incorporating topological constraints was discussed in Part 1 (2004. J. Mech. Phys. Solids 52, 2617-2660) of this work. In this follow-up contribution we extend the non-affine microsphere model towards the description of time-dependent viscoelastic effects. The viscoelastic network model is constructed by an additive split of the overall response into elastic equilibrium-stress and viscoelastic overstress contributions. The equi...
A Numerical Investigationof VMS-POD Model for Darcy-Brinkman Equations
Güler Eroğlu, Fatma; Kaya Merdan, Songül; Rebholz, Leo (2018-07-06)
We extend the variational multiscale proper orthogonal decomposition reduced order modeling (VMSPOD) to flows governed by double diffusive convection. We present stability and convergence analyses for it, and give results for numerical tests on a benchmark problem which show it is an effective approach.
An algorithm to generate toroidal and helical cage structures using pentagons, hexagons and heptagons
Yazgan, E; Tasci, E; Erkoc, A (World Scientific Pub Co Pte Lt, 2004-02-01)
An algorithm to generate toroidal or helical cage structures has been developed. Any toroidal or helical structure can be generated following four stages. In the first stage a Fonseca type unit cell and its symmetrical counterpart is formed which represents one-fifth of a toroid. In the second stage one-fifth fragment of the torus is fully obtained by applying geometry optimization to the structure obtained in the first stage. In the third stage the torus fragment obtained in the second stage is reproduced ...
Citation Formats
M. H. Aksel, A. MACPHERSON, and P. HILTON, “A FINITE-ELEMENT STUDY OF FRONTOGENESIS,” MONTHLY WEATHER REVIEW, pp. 1053–1066, 1984, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/54380.