Simulation of air flow–yarn interaction inside the main nozzle of an air jet loom

2017 ◽  
Vol 88 (10) ◽  
pp. 1173-1183 ◽  
Author(s):  
Akil Osman ◽  
Benny Malengier ◽  
Simon De Meulemeester ◽  
Jozef Peeters ◽  
Jan Vierendeels ◽  
...  
Keyword(s):  
Air Flow ◽  
Three Dimensional ◽  
Weft Yarn ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Air Jet ◽  
A Chain ◽  
Air Jet Loom ◽  
Insertion Process ◽  
Good Agreement

The main nozzle of an air jet loom plays an essential role in the weft insertion process. This role involves sucking the weft yarn from the prewinder and launching it into the reed. Simulating the dynamic behavior of the weft yarn inside the main nozzle involves fluid–structure interaction (FSI). In this work, one-way and two-way FSI simulations of air flow–yarn interaction inside a main nozzle have been performed. A three-dimensional model of the flexible weft yarn, consisting of a chain of line segments, and a two-dimensional axisymmetric model of the supersonic flow have been developed and coupled to perform these simulations. The results of the simulations are compared quantitatively and qualitatively with experimental results. Good agreement has been found between the results of the two-way FSI simulations and the experiment. The coupled fluid and structure models provide an effective numerical tool to optimize the geometry of the main nozzle based on the calculated motion and speed of the weft yarn.

Use of a three-dimensional model to predict heavy metal (copper) fluxes in the Oujiang estuary

2014 ◽  
Vol 69 (6) ◽  
pp. 1334-1343 ◽  
Author(s):  
Shasha Lu ◽  
Ruijie Li ◽  
Xiaoming Xia ◽  
Jun Zheng
Keyword(s):  
River Discharge ◽  
Water Surface ◽  
Three Dimensional ◽  
Measured Data ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Pollutant Concentrations ◽  
Suspended Sediment Concentrations ◽  
Adsorption Desorption ◽  
Good Agreement

Measuring pollutant concentrations in major tributaries is the standard method for establishing pollutant fluxes to the sea. However, this method is costly and difficult, and may be subject to a great deal of uncertainty due to the presence of unknown sources. This uncertainty presents challenges to managers and scientists in reducing contaminant discharges to water bodies. As one less costly method, a three-dimensional model was developed and used to predict pollutant fluxes to the sea. The sorptive contaminant model was incorporated into hydrodynamic and sediment models. Adsorption–desorption of copper by sediments in the Oujiang estuary were described using Henry's law. The model was validated using measured data for water surface elevations, flow velocity/direction, suspended sediment concentrations, and the proportion of copper sorbed to sediment. The validated model was then applied to predict fluxes of copper. Combined with the measured data, the copper concentration in the Oujiang River discharge was calculated as 13.0 μg/L and copper fluxes were calculated as 52 t in 2010. This copper flux prediction was verified using measured dissolved copper concentrations. Comparisons between the modeled and measured results showed good agreement at most stations, demonstrating that copper flux prediction in the Oujiang estuary was reasonably accurate.

A Three Dimensional Model for Generating the Texture in B-Scan Ultrasound Images

1983 ◽  
Vol 5 (3) ◽  
pp. 253-279 ◽  
Author(s):  
Mitchell M. Goodsitt ◽  
Ernest L. Madsen ◽  
James A. Zagzebski
Keyword(s):  
Three Dimensional ◽  
Time Dependent ◽  
Ultrasound Images ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Gray Scale ◽  
Receiver System ◽  
Gray Scale Image ◽  
Theory And Experiment ◽  
Good Agreement

A three-dimensional model for production of gray scale texture in ultrasound B-mode images is described. The model computes time-dependent echo signals resulting from scattering of acoustic pulses by particles randomly distributed in an attenuating medium and transforms these signals into a gray scale image. Specific transducer and pulser-receiver characteristics are accounted for, as well as the three-dimensional nature of the problem, without loss of computational efficiency. The model generates texture that closely corresponds to that found experimentally in ultrasound images of tissue-mimicking phantoms. The dependence of the texture upon the depth of the region that was scanned and on the characteristics of the transducer-receiver system were clearly demonstrated. Good agreement between theory and experiment was found for the texture in phantoms containing simulated spherical low-scatter tumors.

A THREE-DIMENSIONAL MODEL OF DISCHARGED COLD WATER JET IN COASTAL AREA

2017 ◽  
Author(s):  
Yasuo Niida ◽  
Yasuo Niida ◽  
Norikazu Nakashiki ◽  
Norikazu Nakashiki ◽  
Shin’ichi Sakai ◽  
...  
Keyword(s):  
Numerical Model ◽  
Coastal Area ◽  
Cold Water ◽  
Three Dimensional ◽  
Coastal Region ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Water Dispersion ◽  
Water Jets ◽  
Good Agreement

In this study, a three-dimensional numerical model for cold water jets in the coastal region is developed for the calculation of not only the initial mixing but also horizontal dispersion above the seabed. The computed velocities and temperatures were compared with the measurements obtained in the scaled hydraulic experiment. The good agreement with measurements confirms the model provides appropriate results for cold water dispersion. Our numerical results indicate that coastal topography is the most important factor in determining areas influenced by discharged cold water.

Flow and Heat Transfer Computations in a Rotating Cavity With Tangential Seal Air Flow

1997 ◽  
Author(s):  
Prabhat Tekriwal
Keyword(s):  
Heat Transfer ◽  
Air Flow ◽  
Three Dimensional ◽  
Thermomechanical Analysis ◽  
Heat Transfer Analysis ◽  
Symmetric Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Life Study ◽  
Analysis And Design

Axi-symmetric and three-dimensional CFD models for a rotating open interdisk cavity have been developed to predict flow, heat transfer, windage power loss and cavity air temperatures as a part of the rotor thermomechanical analysis and design life study. The cavity has a tangential (axial and circumferential) seal air flow above it. The rotational Reynolds number is 4.8 × 106 and the non-dimensional seal flow rate is 9.8 × 104. Measured wall temperatures are used as boundary conditions in the model. The axi-symmetric model smears the cavity bolts as 360° continuous rings and therefore ignores the bolts pumping effect. The windage loss calculation from the axi-symmetric model is in good agreement with the experimental data in the literature. The heat transfer coefficient values from the axi-symmetric and three-dimensional models are comparable in most of the regions apart from near the bolts. Also, the three-dimensional model simulates the bolt pumping effects and yields a much higher windage loss value, which in turn raises the cavity air temperature. It is concluded that a three-dimensional model is necessary for an accurate heat transfer analysis.

A THREE-DIMENSIONAL MODEL OF DISCHARGED COLD WATER JET IN COASTAL AREA

2017 ◽  
Author(s):  
Yasuo Niida ◽  
Yasuo Niida ◽  
Norikazu Nakashiki ◽  
Norikazu Nakashiki ◽  
Shin’ichi Sakai ◽  
...  
Keyword(s):  
Numerical Model ◽  
Coastal Area ◽  
Cold Water ◽  
Three Dimensional ◽  
Coastal Region ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Water Dispersion ◽  
Water Jets ◽  
Good Agreement

In this study, a three-dimensional numerical model for cold water jets in the coastal region is developed for the calculation of not only the initial mixing but also horizontal dispersion above the seabed. The computed velocities and temperatures were compared with the measurements obtained in the scaled hydraulic experiment. The good agreement with measurements confirms the model provides appropriate results for cold water dispersion. Our numerical results indicate that coastal topography is the most important factor in determining areas influenced by discharged cold water.

Toward three-dimensional modeling of the interaction between the air flow and a clamped–free yarn inside the main nozzle of an air jet loom

2018 ◽  
Vol 89 (6) ◽  
pp. 914-925 ◽  
Author(s):  
Akil Osman ◽  
Lucas Delcour ◽  
Ine Hertens ◽  
Jan Vierendeels ◽  
Joris Degroote
Keyword(s):  
Air Flow ◽  
Three Dimensional ◽  
Initial Position ◽  
Weft Yarn ◽  
Arbitrary Lagrangian Eulerian ◽  
Flexible Cylinder ◽  
Normal Forces ◽  
Wave Characteristics ◽  
Three Dimensional Modeling ◽  
Air Jet

In air jet looms, the weft yarn is transported from the prewinder to the reed by means of an air flow. In this work, the motion of a yarn inside a main nozzle during the first stage of an insertion process is modeled and analyzed. In this stage, the weft yarn is clamped at one side and free at the other side. Therefore, the deformation waves of a clamped–free yarn are modeled. A three-dimensional, two-way, fluid–structure interaction simulation has been performed in which the yarn is represented as a flexible cylinder and the arbitrary Lagrangian–Eulerian technique is employed. The results of the simulation have been compared quantitatively and qualitatively with experiments. It was, however, not possible to match the initial position and stress state of the yarn in the simulations to that in the experiments. This causes large differences between the simulated and measured yarn positions and wave characteristics, especially at the beginning. The agreement between experimental and simulated wave characteristics notably improves as time progresses, but substantial differences remain. Analyzing the overall motion of the yarn inside the main nozzle shows that the mixing region, where the shocks are located, can be considered as an excitation point. In this point, the aerodynamic normal forces are high if the yarn is not located on the axis of the main nozzle. All deformation waves start from the mixing region and propagate along the yarn.

Finite Element Simulation on Stress of Steel Sphere Shell

2012 ◽  
Vol 532-533 ◽  
pp. 297-300
Author(s):  
Chang Li Song ◽  
Jing Ji
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Steel Sphere ◽  
Element Simulation ◽  
Good Agreement

In order to verify correctness of two-dimensional axisymmetric finite element model, this paper carries out axial symmetry analysis of the steel ball shell by ANSYS software and 2-D finite element model is established. The radial and tangential stress distribution is acquired, through comparison with the theoretical solution, both are in good agreement. So it is feasible to simulate the three-dimensional model by finite element axisymmetrical two-dimensional model.

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