Eulerian Bond Graphs for Fluid Continuum Dynamics Modeling

1996 ◽  
Vol 118 (1) ◽  
pp. 48-57 ◽  
Author(s):  
E. P. Fahrenthold ◽  
M. Venkataraman
Keyword(s):  
Compressible Flows ◽  
System Modeling ◽  
General Purpose ◽  
Dynamics Modeling ◽  
Modeling Tools ◽  
Element Discretization ◽  
Inertia Effects ◽  
Flow Geometry ◽  
Viscous Compressible Flows ◽  
Continuum Dynamics

The development of high resolution, general purpose models of viscous, compressible flows is extremely difficult with existing system dynamics modeling tools. Published work admits to significant limitations, with regards to the treatment of flow geometry, inertia effects, or mass and energy convection. Combining a finite element discretization scheme with a bond graph based model formulation procedure provides a very general purpose tool for continuum fluid system modeling.

Lagrangian Bond Graphs for Solid Continuum Dynamics Modeling

1994 ◽  
Vol 116 (2) ◽  
pp. 178-192 ◽  
Author(s):  
E. P. Fahrenthold ◽  
J. D. Wargo
Keyword(s):  
Finite Element ◽  
Bond Graph ◽  
Dynamics Modeling ◽  
Bond Graphs ◽  
Element Discretization ◽  
Large Order ◽  
Wide Range ◽  
Bond Graph Modeling ◽  
Continuum Dynamics ◽  
Fixed Bond

The limitations of existing continuum bond graph modeling techniques have effectively precluded their use in large order problems, where nonrepetitive graph structures and causal patterns are normally present. As a result, despite extensive publication of bond graph models for continuous systems simulations, bond graph methods have not offered a viable alternative to finite element analysis for the vast majority of practical problems. However, a new modeling approach combining Lagrangian (mass fixed) bond graphs with a selected finite element discretization scheme allows for direct simulation of a wide range of large order solid continuum dynamics problems. With appropriate modifications, including the use of Eulerian (space fixed) bond graphs, the method may be extended to include fluid dynamics modeling.

Dynamics of Curved Beams Undergoing Large Overall Motions Using the Mode Decomposition Concept

1993 ◽  
Author(s):  
Joseph F. D’Costa ◽  
Henryk K. Stolarski ◽  
Arthur G. Erdman
Keyword(s):  
Multibody Systems ◽  
Inertial Frame ◽  
Curved Beams ◽  
Nonlinear Formulation ◽  
Element Discretization ◽  
Inertia Effects ◽  
Mode Decomposition ◽  
Curved Elements ◽  
Finite Bending ◽  
Locking Phenomena

Abstract A fully nonlinear formulation for the dynamics of initially curved and twisted beams, undergoing arbitrary spatial motions, is presented. The formulation admits finite bending, shearing and extension of the beam. The Mode decomposition method is employed to modify the strains in the finite element discretization process leading to the elimination of shear and membrane locking phenomena that arise in curved elements. The model incorporates all inertia effects and is capable of accurately capturing the phenomena of dynamic stiffening due to the coupling of the axial and membrane forces to the flexural deformation. All motion is referred to the inertial frame. The nonlinear formulation is suitable for modeling flexible multibody systems. Examples are presented to illustrate the validity of the proposed formulation.

scholarly journals Fluid Dynamics Android Application: An Efficient Semi-Implicit Solver for Compressible Flows

2019 ◽  
Author(s):  
Shivam Singhal ◽  
Yayati Gupta ◽  
Ashish Garg
Keyword(s):  
Fluid Dynamics ◽  
Numerical Methods ◽  
Language Learning ◽  
Compressible Flows ◽  
General Purpose ◽  
Android Application ◽  
Standard Atmosphere ◽  
Expansion Fan ◽  
Implicit Solver ◽  
Isentropic Flows

The computing power of smartphones has not received considerable attention in the mainstream education system. Most of the education-oriented smartphone applications (apps) are limited to general purpose services like Massive Open Online Courses (MOOCs), language learning, and calculators (performing basic mathematical calculations). Greater potential of smartphones lies in educators and researchers developing their customized apps for learners in highly specific domains. In line with this, we present Fluid Dynamics, a highly accurate Android application for measuring flow properties in compressible flows. This app can determine properties across the stationary normal and oblique shock, moving normal shock and across Prandtl $-$ Meyer expansion fan. This app can also measure isentropic flows, Fanno flows, and Rayleigh flows. The functionality of this app is also extended to calculate properties in the atmosphere by assuming the International Standard Atmosphere (ISA) relations and also flows across the Pitot tube. Such measurements are complicated and time-consuming since the relations are implicit and hence require the use of numerical methods, which give rise to repetitive calculations. The app is an efficient semi-implicit solver for gas dynamics formulations and uses underlying numerical methods for the computations in a graphical user interface (GUI), thereby easing and quickening the learning of concerned users. The app is designed for the Android operating system, the most ubiquitous and capable surveillance platform, and its calculations are based on JAVA based code methodology. In order to check its accuracy, the app's results are validated against the existing data given in the literature.

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