Porosity models and computational methods for compressible-flow aerodynamics of parachutes with geometric porosity

2017 ◽  
Vol 27 (04) ◽  
pp. 771-806 ◽  
Author(s):  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Taro Kanai
Keyword(s):  
Compressible Flow ◽  
Computational Methods ◽  
Computational Analysis ◽  
Computational Framework ◽  
Design Studies ◽  
Analysis And Design ◽  
Structure Interaction ◽  
Main Components ◽  
Spacecraft Parachutes ◽  
Supg Method

Spacecraft-parachute designs quite often include “geometric porosity” created by the hundreds of gaps and slits that the flow goes through. Computational fluid–structure interaction (FSI) analysis of these parachutes with resolved geometric porosity would be exceedingly challenging, and therefore accurate modeling of the geometric porosity is essential for reliable FSI analysis. The space–time FSI (STFSI) method with the homogenized modeling of geometric porosity has proven to be reliable in computational analysis and design studies of Orion spacecraft parachutes in the incompressible-flow regime. Here we introduce porosity models and ST computational methods for compressible-flow aerodynamics of parachutes with geometric porosity. The main components of the ST computational framework we use are the compressible-flow ST SUPG method, which was introduced earlier, and the compressible-flow ST Slip Interface method, which we introduce here. The computations we present for a drogue parachute show the effectiveness of the porosity models and ST computational methods.

Fluid-Structure Interaction Modeling of Spacecraft Parachutes for Simulation-Based Design

2011 ◽  
Vol 79 (1) ◽  
Author(s):  
Kenji Takizawa ◽  
Timothy Spielman ◽  
Creighton Moorman ◽  
Tayfun E. Tezduyar
Keyword(s):  
Computer Modeling ◽  
Fluid Structure Interaction ◽  
Flow Simulation ◽  
Control Line ◽  
Fluid Structure ◽  
Analysis And Design ◽  
Structure Interaction ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Spacecraft Parachutes

Even though computer modeling of spacecraft parachutes involves a number of numerical challenges, advanced techniques developed in recent years for fluid-structure interaction (FSI) modeling in general and for parachute FSI modeling specifically have made simulation-based design studies possible. In this paper we focus on such studies for a single main parachute to be used with the Orion spacecraft. Although these large parachutes are typically used in clusters of two or three parachutes, studies for a single parachute can still provide valuable information for performance analysis and design and can be rather extensive. The major challenges in computer modeling of a single spacecraft parachute are the FSI between the air and the parachute canopy and the geometric complexities created by the construction of the parachute from “rings” and “sails” with hundreds of gaps and slits. The Team for Advanced Flow Simulation and Modeling has successfully addressed the computational challenges related to the FSI and geometric complexities, and has also been devising special procedures as needed for specific design parameter studies. In this paper we present parametric studies based on the suspension line length, canopy loading, and the length of the overinflation control line.

Comparison and Analysis of Computational Methods for Identifying N6 - methyladenosine Sites in Saccharomyces Cerevisiae

2020 ◽  
Vol 26 ◽  
Author(s):  
Pengmian Feng ◽  
Lijing Feng ◽  
Chaohui Tang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Computational Methods ◽  
Computational Analysis ◽  
Computational Prediction ◽  
Experimental Methods ◽  
Biological Processes ◽  
Biological Functions ◽  
Precise Location ◽  
Future Directions ◽  
The Past

Background and Purpose: N 6 -methyladenosine (m6A) plays critical roles in a broad set of biological processes. Knowledge about the precise location of m6A site in the transcriptome is vital for deciphering its biological functions. Although experimental techniques have made substantial contributions to identify m6A, they are still labor intensive and time consuming. As good complements to experimental methods, in the past few years, a series of computational approaches have been proposed to identify m6A sites. Methods: In order to facilitate researchers to select appropriate methods for identifying m6A sites, it is necessary to give a comprehensive review and comparison on existing methods. Results: Since researches on m6A in Saccharomyces cerevisiae are relatively clear, in this review, we summarized recent progresses on computational prediction of m6A sites in S. cerevisiae and assessed the performance of existing computational methods. Finally, future directions of computationally identifying m6A sites were presented. Conclusion: Taken together, we anticipate that this review will provide important guides for computational analysis of m 6A modifications.

GDVFS: A New Toolkit for Analysis and Design of Vegetative Filter Strips Using VFSMOD

2010 ◽  
Vol 45 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Ramesh P. Rudra ◽  
Bahram Gharabaghi ◽  
Saleh Sebti ◽  
Neelam Gupta ◽  
Ashwini Moharir
Keyword(s):  
Phosphorus Removal ◽  
Design Tool ◽  
Vegetative Filter Strips ◽  
Bacteria Transport ◽  
Filter Strips ◽  
Analysis And Design ◽  
Vegetative Filter Strip ◽  
Removal Efficiencies ◽  
Computational Procedures ◽  
Main Components

Abstract The Guelph design tool for vegetative filter strips, GDVFS, is a toolkit for the analysis and design of vegetative filter strips (VFSs). The upland hydrology model UH and the vegetative filter strip model VFSMOD (the two main components of GDVFS) were adopted from an existing interface (VFSMOD-W), and new nutrient and bacteria transport add-ons for UH and VFSMOD were incorporated into GDVFS. Other utilities and tools were also included in GDVFS to provide a capable toolkit for the analysis and design of VFSs. The published evaluation of computational procedures used in GDVFS indicates that these procedures perform very well in the estimation of VFS sediment and phosphorus removal efficiencies. According to these results, comparison of the predicted and observed values for sediment and phosphorus removal efficiencies indicates 10 and 20% error, respectively. This paper provides descriptions on the capabilities and methodology followed in the GDVFS toolkit.

Analysis and Design of Elastic Beams: Computational Methods

2003 ◽  
Vol 56 (3) ◽  
pp. B38-B40
Author(s):  
WD Pilkey, ◽  
SN Krivoshapko,
Keyword(s):  
Computational Methods ◽  
Analysis And Design ◽  
Elastic Beams

scholarly journals Host−Guest Complexes with Protein−Ligand-like Affinities: Computational Analysis and Design

2009 ◽  
Vol 131 (11) ◽  
pp. 4012-4021 ◽  
Author(s):  
Sarvin Moghaddam ◽  
Yoshihisa Inoue ◽  
Michael K. Gilson
Keyword(s):  
Computational Analysis ◽  
Analysis And Design

scholarly journals Two-Way Fluid-Structure Coupling in Vibration and Damping Analysis of an Oscillating Hydrofoil

2014 ◽  
Author(s):  
T. Liaghat ◽  
F. Guibault ◽  
L. Allenbach ◽  
B. Nennemann
Keyword(s):  
Fluid Structure Interaction ◽  
Mesh Size ◽  
Main Concern ◽  
Time Step ◽  
Flowing Fluid ◽  
Fluid Structure ◽  
Analysis And Design ◽  
Structure Interaction ◽  
Hydrodynamic Damping ◽  
Hydraulic Machines

Fluid-structure interaction (FSI) and unavoidable vibrations are important characteristics in the operation of hydropower structures and must be taken into account in the analysis and design of such equipment. Hydrodynamic damping influences the amplitude of vibrations and is directly related to fatigue problems in hydraulic machines which are of great importance. The aim of this study is to investigate the coupled effects of flowing fluid on a simplified hydrofoil by using three-dimensional two-way fluid-structure interaction modeling, in order to determine its importance in predicting vibration amplitudes and damping. The effect of considering different flow velocities is also investigated in the present study. The results of this research are compared with those obtained from experiments done by ANDRITZ [1]. The influences of mesh size and time step are also studied. Our results indicate that considering FSI in predicting the frequencies of the fluctuating fluid forces in practical problems might be ignored if the main concern of the analysis is to check the possibility of resonance. However, FSI must be included in the modeling when we aim to predict the influence of the fluid on the damping behavior in the hydrofoil vibration.

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