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.

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 DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 2: Model validation

2017 ◽  
Author(s):  
Albrecht v. Boetticher ◽  
Jens M. Turowski ◽  
Brian W. McArdell ◽  
Dieter Rickenmann ◽  
Marcel Hürlimann ◽  
...  
Keyword(s):  
Debris Flow ◽  
Model Validation ◽  
Material Properties ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Clay Content ◽  
Friction Angle ◽  
Angle Of Repose ◽  
Model Parameters

Abstract. Here we present validation tests of the fluid dynamic solver presented in in v. Boetticher et al. (2016), simulating both laboratory-scale and large-scale debris-flow experiments. The new solver combines a Coulomb viscosplastic rheological model with a Herschel-Bulkley model based on material properties and rheological characteristics of the analysed debris flow. For the selected experiments in this study, all necessary material properties were known – the content of sand, clay (including its mineral composition) and gravel (including its friction angle) as well as the water content. We show that given these measured properties, two model parameters are sufficient for calibration, and a range of experiments with different material compositions can be reproduced by the model without recalibration. One calibration parameter, the Herschel–Bulkley exponent, was kept constant for all simulations. The model validation focuses on different case studies illustrating the sensitivity of debris flows to water and clay content, channel curvature, channel roughness and the angle of repose. We characterize the accuracy of the model using experimental observations of flow head positions, front velocities, run-out patterns and basal pressures.

scholarly journals DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 1: Model description

2016 ◽  
Vol 9 (9) ◽  
pp. 2909-2923 ◽  
Author(s):  
Albrecht von Boetticher ◽  
Jens M. Turowski ◽  
Brian W. McArdell ◽  
Dieter Rickenmann ◽  
James W. Kirchner
Keyword(s):  
Fluid Dynamic ◽  
Three Dimensional ◽  
Clay Content ◽  
Friction Angle ◽  
Rheological Parameters ◽  
Model Description ◽  
Model Parameters ◽  
Navier Stokes Equation ◽  
Two Fluids ◽  
Rate Dependent

Abstract. Here, we present a three-dimensional fluid dynamic solver that simulates debris flows as a mixture of two fluids (a Coulomb viscoplastic model of the gravel mixed with a Herschel–Bulkley representation of the fine material suspension) in combination with an additional unmixed phase representing the air and the free surface. We link all rheological parameters to the material composition, i.e., to water content, clay content, and mineral composition, content of sand and gravel, and the gravel's friction angle; the user must specify only two free model parameters. The volume-of-fluid (VoF) approach is used to combine the mixed phase and the air phase into a single cell-averaged Navier–Stokes equation for incompressible flow, based on code adapted from standard solvers of the open-source CFD software OpenFOAM. This effectively single-phase mixture VoF method saves computational costs compared to the more sophisticated drag-force-based multiphase models. Thus, complex three-dimensional flow structures can be simulated while accounting for the pressure- and shear-rate-dependent rheology.

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.

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

Comparisons of Rotordynamic Characteristics Predictions for Annular Gas Seals Using the Transient Computational Fluid Dynamic Method Based on Different Single-Frequency and Multifrequency Rotor Whirling Models

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Zhenping Feng
Keyword(s):  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Single Frequency ◽  
Solution Technique ◽  
Model Parameters ◽  
Multiple Frequency ◽  
Rotordynamic Coefficients ◽  
Gas Seals ◽  
Cfd Method

The three-dimensional (3D) transient computational fluid dynamic (CFD) method was proposed to predict rotordynamic coefficients for annular gas seals. This transient CFD method uses unsteady Reynolds-Averaged Navier–Stokes (RANS) solution technique and mesh deformation theory, which requires a rotor whirling model as the rotor excitation signal to solve the transient leakage flow field in seal and obtain the transient fluid response forces on the rotor surface. A fully partitioned pocket damper seal (FPDS) was taken as the test object to validate the present numerical method. Comparisons were made between experimental data and rotordynamic coefficient predictions using the three variations of the single-frequency and multiple-frequency rotor whirling models: (1) one-dimensional whirling model, (2) circular orbit whirling model, and (3) elliptical orbit whirling model. The numerical results show that the rotordynamic coefficients predicted by the present CFD method and six different rotor whirling models all agree well with the experiment data, and nearly coincide for all rotor whirling models. The proposed transient CFD method can be used to perform a reasonably accurate prediction of the frequency-dependent rotordynamic coefficients for annular gas seals based on any one of the present six rotor whirling models, as long as ensuring the combination of these whirling model parameters captures the small perturbation theory. The rotor whirling parameters such as whirling orbit, amplitude, and frequency number are important in predicting rotor whirling motion and fluid response forces, but have almost no effect on the computed rotordynamic coefficients. The benefit of the multiple-frequency rotor whirling models is the ability to calculate accurate rotordynamic coefficients of annular gas seals in a wide frequency range with a simulation time on the order of one-tenth the cost of the single-frequency whirling models.

scholarly journals DebrisInterMixing-2.3: a finite volume solver for three-dimensional debris-flow simulations with two calibration parameters – Part 2: Model validation with experiments

2017 ◽  
Vol 10 (11) ◽  
pp. 3963-3978 ◽  
Author(s):  
Albrecht von Boetticher ◽  
Jens M. Turowski ◽  
Brian W. McArdell ◽  
Dieter Rickenmann ◽  
Marcel Hürlimann ◽  
...  
Keyword(s):  
Debris Flow ◽  
Model Validation ◽  
Material Properties ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Clay Content ◽  
Angle Of Repose ◽  
Model Parameters ◽  
Channel Curvature

Abstract. Here, we present validation tests of the fluid dynamic solver presented in von Boetticher et al. (2016), simulating both laboratory-scale and large-scale debris-flow experiments. The new solver combines a Coulomb viscoplastic rheological model with a Herschel–Bulkley model based on material properties and rheological characteristics of the analyzed debris flow. For the selected experiments in this study, all necessary material properties were known – the content of sand, clay (including its mineral composition) and gravel as well as the water content and the angle of repose of the gravel. Given these properties, two model parameters are sufficient for calibration, and a range of experiments with different material compositions can be reproduced by the model without recalibration. One calibration parameter, the Herschel–Bulkley exponent, was kept constant for all simulations. The model validation focuses on different case studies illustrating the sensitivity of debris flows to water and clay content, channel curvature, channel roughness and the angle of repose. We characterize the accuracy of the model using experimental observations of flow head positions, front velocities, run-out patterns and basal pressures.

A NEW MODEL FOR REFRIGERANT CONDENSATION ON THE OUTSIDE OF THREE-DIMENSIONAL ENHANCED TUBES

1998 ◽  
Author(s):  
Alberto Cavallini ◽  
Davide Del Col ◽  
Luca Doretti ◽  
Luisa Rossetto ◽  
Giovanni Antonio Longo
Keyword(s):  
Three Dimensional ◽  
New Model ◽  
Enhanced Tubes
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