A Three-Dimensional Numerical Fluid Dynamic Model of Antigen–Antibody Surface Adsorption on Piezoelectric Immunosensors

2002 ◽  
Vol 30 (10) ◽  
pp. 1313-1322 ◽  
Author(s):  
Deganit Barak-Shinar ◽  
Moshe Rosenfeld ◽  
Einat Zisman ◽  
Shimon Abboud
Keyword(s):  
Dynamic Model ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Surface Adsorption ◽  
Antigen Antibody

Study on the aerodynamic noise of internal flow of regenerative flow compressors for a fuel-cell car

2013 ◽  
Vol 228 (7) ◽  
pp. 1155-1174 ◽  
Author(s):  
Qiang Kang ◽  
Shuguang Zuo ◽  
Kaijun Wei
Keyword(s):  
Finite Element ◽  
Fuel Cell ◽  
Dynamic Model ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Internal Flow ◽  
Aerodynamic Noise ◽  
Noise Sources ◽  
Element Analysis ◽  
Regenerative Flow

The regenerative flow compressor used in fuel-cell cars generates high aerodynamic noise, which is the main source of noise. Compared with the research on centrifugal or axial turbomachinery, research on the noise of regenerative flow compressors is far from adequate. This paper presents the on-going work on it at Tongji University based on both experimental and computational works. In this study, a three-dimensional unsteady computational fluid dynamic model of the compressor was constructed with the large eddy approach. The pressure fluctuation, vortex noise source and Ffowcs William-Hawkings (FW-H) method were used to analyze the characteristics of the aerodynamic noise sources. Additionally, the far-field aerodynamic noise generated by the internal flow of the compressor was predicted using the aeroacoustic finite element method. The simulation results were validated with the experimental data. It was found that combining the fluid dynamic model and aeroacoustic finite element analysis promising results for aerodynamic noise prediction of compressors could be produced. The effects of the impeller parameters on the aerodynamic noise of the compressor were also studied.

Study of wind–vehicle–bridge system of suspended monorail during the meeting of two trains

2019 ◽  
Vol 22 (8) ◽  
pp. 1988-1997 ◽  
Author(s):  
Yu-long Bao ◽  
Huo-yue Xiang ◽  
Yong-le Li ◽  
Chuan-jin Yu ◽  
Yi-chao Wang
Keyword(s):  
Dynamic Model ◽  
Dynamic Method ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Aerodynamic Coefficients ◽  
Negative Contribution ◽  
Multi Body ◽  
Fluctuating Wind ◽  
Body Dynamic ◽  
Bridge System

Based on the theories of aerodynamics, bridge dynamics, and vehicle dynamics, the aerodynamic performances and the vibration characteristics of the wind–vehicle–bridge coupling system of two suspended monorail trains passing each other are analyzed. First, a wind model is presented with spectral representation method, the aerodynamic coefficients of bridge and vehicles before and after meeting are obtained through computational fluid dynamic method, and wind tunnel tests are conducted to verify the aerodynamic coefficients. Then, a vehicle dynamic model and a bridge dynamic model are established with the multi-body dynamic method and finite element method. Finally, a three-dimensional wind–vehicle–bridge coupled vibration model is established in this article using the multi-body dynamic software SIMPACK. The effects of average wind and fluctuating wind on the wind–vehicle–bridge system are studied. It is shown that the aerodynamic coefficients vary greatly under different combinations of vehicle–bridge system. The responses of the leeward vehicle change abruptly at the beginning and the end of the meeting of the two trains. And the mean wind speed has a great negative contribution to the acceleration of leeward vehicle. The lateral responses of suspended monorail vehicle are sensitive to the fluctuating wind. The roll angle of vehicle is presented for describing the running safety of the suspended monorail vehicles.

scholarly journals Configurable 3D Rowing Model Renders Realistic Forces on a Simulator for Indoor Training

2020 ◽  
Vol 10 (3) ◽  
pp. 734 ◽  
Author(s):  
Ekin Basalp ◽  
Patrick Bachmann ◽  
Nicolas Gerig ◽  
Georg Rauter ◽  
Peter Wolf
Keyword(s):  
Dynamic Model ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Smooth Transition ◽  
Model Parameters ◽  
Interaction Forces ◽  
New Model ◽  
Perceived Realism ◽  
Water Interaction ◽  
Resistive Forces

In rowing, rowers need outdoor and indoor training to develop a proficient technique. Although numerous indoor rowing machines have been proposed, none of the devices can realistically render the haptic, visual, and auditory characteristics of an actual rowing scenario. In our laboratory, we developed a simulator to support rowing training indoors. However, rendered forces with the initial rowing model, which was based on a simplified fluid dynamic model that approximated the drag/lift forces, were not perceived realistic enough for indoor training by expert rowers. Therefore, we implemented a new model for the blade–water interaction forces, which incorporates the three-dimensional rotation of the oar and continuously adjusts drag/lift coefficients. Ten expert rowers were asked to evaluate both models for various rowing aspects. In addition, the effect of individualization of model parameters on the perceived realism of rowing forces was elaborated. Based on the answers of the experts, we concluded that the new model rendered realistically resistive forces and ensured a smooth transition of forces within a rowing cycle. Additionally, we found that individualization of parameters significantly improved the perceived realism of the simulator. Equipped with a configurable rowing model, our simulator provides a realistic indoor training platform for rowers.

Three-Dimensional Fluid Dynamic Model for the Prediction of Microfiltration Membrane Fouling and Flux Decline

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Seounghyun Ham ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor ◽  
John E. Wentz
Keyword(s):  
Pore Size ◽  
Dynamic Model ◽  
Membrane Fouling ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Design Tool ◽  
Pore Geometry ◽  
Membrane Pore ◽  
Flux Decline ◽  
Pore Size Distributions

A three-dimensional fluid dynamic model is developed to predict flux decline due to membrane fouling during the microfiltration of semisynthetic metalworking fluids. The model includes surface forces as well as hydrodynamic effects. Two pore model geometries are developed based on sintered aluminum oxide membranes. Simulations conducted using a single-pathway pore geometry illustrate the ability of the three-dimensional model to represent how flow continues through a partially blocked pore and how partial blocking reduces effective cross-sectional area. A four-disk pore geometry is used to compare flux decline behavior for different pore size distributions representing a new membrane and a membrane that had become partially blocked. Flux decline results are found to be consistent with published experimental results for similar membranes. An example shows how the three-dimensional fluid dynamic model may be used to determine the best membrane pore size distribution for a given situation and therefore demonstrates its overall utility as a design tool.

scholarly journals Coupled Fluid–Solid Numerical Simulation for Flow Field Characteristics and Supporting Performance of Flexible Support Cylindrical Gas Film Seal

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  
Keyword(s):  
Flow Field ◽  
Film Thickness ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Flexible Support ◽  
Flow Field Characteristics

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.

scholarly journals Simulation of Hydraulic Cylinder Cushioning

2021 ◽  
Vol 13 (2) ◽  
pp. 494
Author(s):  
Antonio Algar ◽  
Javier Freire ◽  
Robert Castilla ◽  
Esteban Codina
Keyword(s):  
Dynamic Model ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Computational Fluid Dynamic Simulation ◽  
Hydraulic Cylinder ◽  
Outlet Port ◽  
Optimal Behavior ◽  
Radial Movement ◽  
Mechanical Shocks ◽  
Radial Gap

The internal cushioning systems of hydraulic linear actuators avoid mechanical shocks at the end of their stroke. The design where the piston with perimeter grooves regulates the flow by standing in front of the outlet port has been investigated. First, a bond graph dynamic model has been developed, including the flow throughout the internal cushion design, characterized in detail by computational fluid-dynamic simulation. Following this, the radial movement of the piston and the fluid-dynamic coefficients, experimentally validated, are integrated into the dynamic model. The registered radial movement is in coherence with the significant drag force estimated in the CFD simulation, generated by the flow through the grooves, where the laminar flow regime predominates. Ultimately, the model aims to predict the behavior of the cushioning during the movement of the arm of an excavator. The analytical model developed predicts the performance of the cushioning system, in coherence with empirical results. There is an optimal behavior, highly influenced by the mechanical stress conditions of the system, subject to a compromise between an increasing section of the grooves and an optimization of the radial gap.

The inlet flow structure of a conceptual open-nose supersonic drone

2021 ◽  
pp. 095441002098304
Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computational Fluid Dynamic Simulation ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Aerodynamic Efficiency ◽  
Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

scholarly journals Fish larvae exploit edge vortices along their dorsal and ventral fin folds to propel themselves

2016 ◽  
Vol 13 (116) ◽  
pp. 20160068 ◽  
Author(s):  
Gen Li ◽  
Ulrike K. Müller ◽  
Johan L. van Leeuwen ◽  
Hao Liu
Keyword(s):  
Larval Fish ◽  
Fish Larvae ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Bony Fish ◽  
The Body ◽  
Functional Explanation ◽  
Image Velocimetry ◽  
Median Fins

Larvae of bony fish swim in the intermediate Reynolds number ( Re ) regime, using body- and caudal-fin undulation to propel themselves. They share a median fin fold that transforms into separate median fins as they grow into juveniles. The fin fold was suggested to be an adaption for locomotion in the intermediate Reynolds regime, but its fluid-dynamic role is still enigmatic. Using three-dimensional fluid-dynamic computations, we quantified the swimming trajectory from body-shape changes during cyclic swimming of larval fish. We predicted unsteady vortices around the upper and lower edges of the fin fold, and identified similar vortices around real larvae with particle image velocimetry. We show that thrust contributions on the body peak adjacent to the upper and lower edges of the fin fold where large left–right pressure differences occur in concert with the periodical generation and shedding of edge vortices. The fin fold enhances effective flow separation and drag-based thrust. Along the body, net thrust is generated in multiple zones posterior to the centre of mass. Counterfactual simulations exploring the effect of having a fin fold across a range of Reynolds numbers show that the fin fold helps larvae achieve high swimming speeds, yet requires high power. We conclude that propulsion in larval fish partly relies on unsteady high-intensity vortices along the upper and lower edges of the fin fold, providing a functional explanation for the omnipresence of the fin fold in bony-fish larvae.

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