Scable Computational Steering System for Visualization of Large-Scale CFD Simulations

2002 ◽  
Author(s):  
Anirudh Modi ◽  
Nilay Sezer-Uzol ◽  
Lyle Long ◽  
Paul Plassmann
Keyword(s):  
Large Scale ◽  
Steering System ◽  
Computational Steering ◽  
Cfd Simulations

Cyclic Breathing Simulations in Large Scale Models of the Lung Airway From the Oronasal Opening to the Terminal Bronchioles

2012 ◽  
Author(s):  
D. Keith Walters ◽  
Greg W. Burgreen ◽  
Robert L. Hester ◽  
David S. Thompson ◽  
David M. Lavallee ◽  
...  
Keyword(s):  
Steady State ◽  
Boundary Conditions ◽  
Large Scale ◽  
Whole Body ◽  
Patient Specific ◽  
Cfd Simulations ◽  
Reduced Order ◽  
Scale Models ◽  
Steady State Simulation ◽  
Conducting Zone

Computational fluid dynamics (CFD) simulations were performed for unsteady periodic breathing conditions, using large-scale models of the human lung airway. The computational domain included fully coupled representations of the orotracheal region and large conducting zone up to generation four (G4) obtained from patient-specific CT data, and the small conducting zone (to G16) obtained from a stochastically generated airway tree with statistically realistic geometrical characteristics. A reduced-order geometry was used, in which several airway branches in each generation were truncated, and only select flow paths were retained to G16. The inlet and outlet flow boundaries corresponded to the oronasal opening (superior), the inlet/outlet planes in terminal bronchioles (distal), and the unresolved airway boundaries arising from the truncation procedure (intermediate). The cyclic flow was specified according to the predicted ventilation patterns for a healthy adult male at three different activity levels, supplied by the whole-body modeling software HumMod. The CFD simulations were performed using Ansys FLUENT. The mass flow distribution at the distal boundaries was prescribed using a previously documented methodology, in which the percentage of the total flow for each boundary was first determined from a steady-state simulation with an applied flow rate equal to the average during the inhalation phase of the breathing cycle. The distal pressure boundary conditions for the steady-state simulation were set using a stochastic coupling procedure to ensure physiologically realistic flow conditions. The results show that: 1) physiologically realistic flow is obtained in the model, in terms of cyclic mass conservation and approximately uniform pressure distribution in the distal airways; 2) the predicted alveolar pressure is in good agreement with previously documented values; and 3) the use of reduced-order geometry modeling allows accurate and efficient simulation of large-scale breathing lung flow, provided care is taken to use a physiologically realistic geometry and to properly address the unsteady boundary conditions.

Large-Scale Simulation of the Clocking Impact of 2D Combustor Profile on a Two Stage High Pressure Turbine

2014 ◽  
Author(s):  
Thomas E. Dyson ◽  
David B. Helmer ◽  
James A. Tallman
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
High Pressure Turbine ◽  
Cfd Simulations ◽  
Two Stage ◽  
Substantial Impact ◽  
Sliding Mesh ◽  
Wall Flow ◽  
End Wall ◽  
Film Flows

This paper presents sliding-mesh unsteady CFD simulations of high-pressure turbine sections of a modern aviation engine in an extension of previously presented work [1]. The simulation included both the first and second stages of a two-stage high-pressure turbine. Half-wheel domains were used, with source terms representing purge and film flows. The end-wall flow-path cavities were incorporated in the domain to a limited extent. The passage-to-passage variation in thermal predictions was compared for a 1D and 2D turbine inlet boundary condition. Substantial impact was observed on both first and second stage vanes despite the mixing from the first stage blade. Qualitative and quantitative differences in surface temperature distributions were observed due to different ratios between airfoil counts in the two domains.

An Approach for Efficient CFD Simulations of an Ejector Air Injection System for Active Aerodynamic Compressor Stabilization

2017 ◽  
Author(s):  
Sebastian Brehm ◽  
Felix Kern ◽  
Jonas Raub ◽  
Reinhard Niehuis
Keyword(s):  
Large Scale ◽  
Armed Forces ◽  
Air Injection ◽  
Injection System ◽  
Cfd Simulations ◽  
Data Set ◽  
Numerical Effort ◽  
Enhance Efficiency ◽  
Set Up ◽  
Novel Concept

The Institute of Jet Propulsion at the University of the German Federal Armed Forces Munich has developed and patented a novel concept of air injection systems for active aerodynamic stabilization of turbo compressors. This so-called Ejector Injection System (EIS) utilizes the ejector effect to enhance efficiency and impact of the aerodynamic stabilization of the Larzac 04 two-spool turbofan engine’s LPC. The EIS design manufactured recently has been subject to CFD and experimental pre-investigations in which the expected ejector effect performance has been proven and the CFD set-up has been validated. Subsequently, optimization of the EIS ejector geometry comes into focus in order to enhance its performance. In this context, CFD parameter studies on the influence of in total 16 geometric and several aerodynamic parameters on the ejector effect are required. However, the existing and validated CFD set-up of the EIS comprises not only the mainly axisymmetric ejector geometry but also the highly complex 3D supply components upstream of the ejector geometry. This is hindering large scale CFD parameter studies due to the numerical effort required for these full 3D CFD simulations. Therefore, an approach to exploit the overall axissymmetry of the ejector geometry is presented within this paper which reduces the numerical effort required for CFD simulations of the EIS by more than 90%. This approach is verified by means of both experimental results as well as CFD predictions of the full 3D set-up. The comprehensive verification data set contains wall pressure distributions and the mass flow rates involved at various Aerodynamic Operating Points (AOP). Furthermore, limitations of the approach are revealed concerning its suitability e.g. to judge the response of the attached compressor of future EIS designs concerning aerodynamic stability or cyclic loading.

CFD Simulations of a Large-Scale Seed Precipitation Tank Stirred with Multiple Intermig Impellers

2015 ◽  
pp. 63-68 ◽  
Author(s):  
Guoquan Zhang ◽  
Hongliang Zhao ◽  
Chao Lv ◽  
Yan Liu ◽  
Ting-an Zhang
Keyword(s):  
Large Scale ◽  
Cfd Simulations ◽  
Seed Precipitation

An Immersive and Interactive Visualization System for Large-Scale CFD

2003 ◽  
Author(s):  
Yuichi Matsuo
Keyword(s):  
Large Scale ◽  
Interactive Visualization ◽  
Cfd Simulations ◽  
Output Data ◽  
Visualization System ◽  
Aerospace Research ◽  
Projection Screen ◽  
Computational Fluid Dynamics Cfd ◽  
Collaboration And Communication ◽  
Rear Projection Screen

We have been long involved in large-scale computational fluid dynamics (CFD) simulations in aerospace research. These days, as the computer power grows, output data from the simulations becomes larger and larger, and we feel that the current visualization methodology has its limitation in understanding. Thus, with the target concepts of reality, collaboration, and communication, we has built an immersive and interactive visualization system with a large-sized wall-type display. The system, which has been in operation since April 2001, is driven by a SGI Onyx 3400 server with 32 CPUs, 64Gbytes memory, and 6 IR3 graphics pipelines, and comprises a 4.6×1.5-meter (15×5-foot) rear projection screen with 3 high-resolution CRT projectors, supporting stereoscopic viewing, easy color/luminosity matching, and accurate edge-blending. The system is mainly used for visualization of large-scale CFD simulations. This paper will describe the new visualization system introduced at the National Aerospace Laboratory of Japan, and the features of the system are discussed while illustrating some typical visualized examples.

Mobile Agent-Based Computational Steering for Distributed Simulation

2007 ◽  
Author(s):  
Yu-Cheng Chou ◽  
David Ko ◽  
Harry H. Cheng ◽  
Roger L. Davis ◽  
Bo Chen
Keyword(s):  
Mobile Agent ◽  
Large Scale ◽  
Distributed Simulation ◽  
Computation Time ◽  
Data Sets ◽  
Computational Steering ◽  
Program Code ◽  
Agent Based ◽  
Diverse Data ◽  
Computational Systems

Two challenging problems in the area of scientific computation are long computation time and large-scale, distributed, and diverse data sets. As the scale of science and engineering applications rapidly expands, these two problems become more manifest than ever. This paper presents the concept of Mobile Agent-based Computational Steering (MACS) for distributed simulation. The MACS allows users to apply new or modified algorithms to a running application by altering certain sections of the program code without the need of stopping the execution and recompiling the program code. The concept has been validated through an application for dynamic CFD data post processing. The validation results show that the MACS has a great potential to enhance productivity and data manageability of large-scale distributed computational systems.

scholarly journals The Effect of Large-Scale Structures on the Stability of Coal-Face Steering

1984 ◽  
Vol 198 (1) ◽  
pp. 29-40 ◽  
Author(s):  
J B Edwards
Keyword(s):  
Control Systems ◽  
Large Scale ◽  
Steering System ◽  
Rigid Support ◽  
Steering Control ◽  
Coal Face ◽  
Large Scale Structures ◽  
General Terms ◽  
Scale Structures ◽  
The Stability

Simplified models of piecewise rigid support structures for power-loaders operating on longwall coal-faces are shown to be amenable to analysis by z-transform methods. Such analysis predicts that increasing sufficiently the length of the sub-sections of the structure (compared to the inherent delay within the vertical steering system of the machine) should stabilize the vertical steering of the entire coalface. Increasing the width of the structure to embrace more than two consecutive cut floors is shown analytically to eliminate the need for electronic tilt-feedback in control systems. In general terms, these analytical predictions are shown to hold good in detailed simulations of the system that eliminate the simplifications demanded by the analytical method. The general conclusion of the work is therefore that an increase in the size of support structure segments can potentially reduce the complexity of steering control systems. The size-increase must be substantial, e.g. to four to five times the size of conventional structures.

Scalable Computational Steering for Visualization/Control of Large-Scale Fluid Dynamics Simulations

2005 ◽  
Vol 42 (4) ◽  
pp. 963-975 ◽  
Author(s):  
Anirudh Modi ◽  
Nilay Sezer-Uzol ◽  
Lyle N. Long ◽  
Paul E. Plassmann
Keyword(s):  
Fluid Dynamics ◽  
Large Scale ◽  
Computational Steering ◽  
Dynamics Simulations
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