scholarly journals Wind Field Synthesis for Animating Wind-induced Vibration

2011 ◽  
Vol 10 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Oyundolgor Khorloo ◽  
Zorig Gunjee ◽  
Batjargal Sosorbaram ◽  
Norishige Chiba
Keyword(s):  
Wind Field ◽  
Structural Engineering ◽  
Computational Cost ◽  
Three Dimensional ◽  
Wind Fields ◽  
Simple Method ◽  
Turbulent Wind ◽  
Key Characteristics ◽  
Induced Motion ◽  
Wind Induced Vibration

We present a simple method to generate three-dimensional frozen and non-frozen turbulent wind fields for use in the animation of wind-induced motion. Our approach uses 1/f^_ noise to match the characteristics of natural wind. By employing a noise-based approach, the complexity as well as computational cost is reduced. Additionally, by considering key characteristics of actual wind that are applied in the structural engineering field, our proposed method is able to produce plausible results in outdoor wind field simulations. In this paper, we describe the implementation results of our proposed method and compare them with other existing approaches used to construct turbulent wind fields. The implementation and visualization are carried out for both two- and three-dimensional scenarios and compared with the results of other well-known methods.

scholarly journals Engineering Comprehensive Model of Complex Wind Fields for Flight Simulation

Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 145
Author(s):  
Jianwei Chen ◽  
Liangming Wang ◽  
Jian Fu ◽  
Zhiwei Yang
Keyword(s):  
Wind Field ◽  
Three Dimensional ◽  
Great Influence ◽  
Spatial Location ◽  
Flight Simulation ◽  
Comprehensive Model ◽  
Flight Trajectory ◽  
Wind Fields ◽  
Wind Field Simulation ◽  
Low Level Jet

A complex wind field refers to the typical atmospheric disturbance phenomena existing in nature that have a great influence on the flight of aircrafts. Aimed at the issues involving large volume of data, complex computations and a single model in the current wind field simulation approaches for flight environments, based on the essential principles of fluid mechanics, in this paper, wind field models for two kinds of wind shear such as micro-downburst and low-level jet plus three-dimensional atmospheric turbulence are established. The validity of the models is verified by comparing the simulation results from existing wind field models and the measured data. Based on the principle of vector superposition, three wind field models are combined in the ground coordinate system, and a comprehensive model of complex wind fields is established with spatial location as the input and wind velocity as the output. The model is applied to the simulated flight of a rocket projectile, and the change in the rocket projectile’s flight attitude and flight trajectory under different wind fields is analyzed. The results indicate that the comprehensive model established herein can reasonably and efficiently reflect the influence of various complex wind field environments on the flight process of aircrafts, and that the model is simple, extensible, and convenient to use.

scholarly journals Non-Stationary Turbulent Wind Field Simulation of Long-Span Bridges Using the Updated Non-Negative Matrix Factorization-Based Spectral Representation Method

2019 ◽  
Vol 9 (24) ◽  
pp. 5506
Author(s):  
Zidong Xu ◽  
Hao Wang ◽  
Han Zhang ◽  
Kaiyong Zhao ◽  
Hui Gao ◽  
...  
Keyword(s):  
Wind Field ◽  
Spectral Representation ◽  
Wind Fields ◽  
Turbulent Wind ◽  
Long Span Bridges ◽  
Long Span ◽  
Spectral Representation Method ◽  
Representation Method ◽  
Turbulent Wind Field ◽  
Non Negative Matrix Factorization

Numerical simulation of the turbulent wind field on long-span bridges is an important task in structural buffeting analysis when it comes to the system non-linearity. As for non-stationary extreme wind events, some efforts have been paid to update the classic spectral representation method (SRM) and the fast Fourier transform (FFT) has been introduced to improve the computational efficiency. Here, the non-negative matrix factorization-based FFT-aided SRM has been updated to generate not only the horizontal non-stationary turbulent wind field, but also the vertical one. Specifically, the evolutionary power spectral density (EPSD) is estimated to characterize the non-stationary feature of the field-measured wind data during Typhoon Wipha at the Runyang Suspension Bridge (RSB) site. The coherence function considering the phase angles is utilized to generate the turbulent wind fields for towers. The simulation accuracy is validated by comparing the simulated and target auto-/cross-correlation functions. Results show that the updated method performs well in generating the non-stationary turbulent wind field. The obtained wind fields will provide the research basis for analyzing the non-stationary buffeting behavior of the RSB and other wind-sensitive structures in adjacent regions.

scholarly journals Multipass Objective Analyses of Doppler Radar Data

2008 ◽  
Vol 25 (10) ◽  
pp. 1845-1858 ◽  
Author(s):  
Mario Majcen ◽  
Paul Markowski ◽  
Yvette Richardson ◽  
David Dowell ◽  
Joshua Wurman
Keyword(s):  
Radial Velocity ◽  
Computational Cost ◽  
Three Dimensional ◽  
Radar Data ◽  
Objective Analysis ◽  
Small Scale ◽  
Velocity Data ◽  
Wind Fields ◽  
Single Pass ◽  
Radial Velocity Data

Abstract This note assesses the improvements in dual-Doppler wind syntheses by employing a multipass Barnes objective analysis in the interpolation of radial velocities to a Cartesian grid, as opposed to a more typical single-pass Barnes objective analysis. Steeper response functions can be obtained by multipass objective analyses; that is, multipass objective analyses are less damping at well-resolved wavelengths (e.g., 8–20Δ, where Δ is the data spacing) than single-pass objective analyses, while still suppressing small-scale (<4Δ) noise. Synthetic dual-Doppler data were generated from a three-dimensional numerical simulation of a supercell thunderstorm in a way that emulates the data collection by two mobile radars. The synthetic radial velocity data from a pair of simulated radars were objectively analyzed to a grid, after which the three-dimensional wind field was retrieved by iteratively computing the horizontal divergence and integrating the anelastic mass continuity equation. Experiments with two passes and three passes of the Barnes filter were performed, in addition to a single-pass objective analysis. Comparison of the analyzed three-dimensional wind fields to the model wind fields suggests that multipass objective analysis of radial velocity data prior to dual-Doppler wind synthesis is probably worth the added computational cost. The improvements in the wind syntheses derived from multipass objective analyses are even more apparent for higher-order fields such as vorticity and divergence, and for trajectory calculations and pressure/buoyancy retrievals.

Three-Dimensional Numerical Simulation of Downburst Wind Occurrded in Wuhan

2011 ◽  
Vol 243-249 ◽  
pp. 5037-5040 ◽  
Author(s):  
Yan Li ◽  
Wei Lian Qu ◽  
Bin Wang ◽  
Yi Fei Wang ◽  
Bai Feng Ji
Keyword(s):  
Wind Field ◽  
Cfd Simulation ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Wind Load ◽  
Structure Design ◽  
Wind Fields ◽  
Transmission Towers ◽  
Weather Phenomenon ◽  
Radiosonde Station

Downburst is a strong downdraft generated below a cumulonimbus cloud, which hits the ground rapidly and causes significant low-level wind shear. It is a strong destructive regional weather phenomenon, which is the main reason for the transmission towers. In recent years, some scholars have researched the finer wind field characteristics and wind load of downburst by using the method of CFD. But the initial conditions are all assumed due to the small synoptic scale, the short lifecycle and the big measurement difficulty of downburst. So downburst wind load can not be taken into account in structural design. Based on the 3-D convective storm numerical model, by inputting temperature, humidity and wind fields detected in Wuhan radiosonde station at 8pm on July,27th,2007, simulation has been accomplished to understand the characteristics of the wind field in the place where the downburst incurred actually. The result provides model data and parameters for CFD simulation, which has directive significance to concern the high intensity downburst wind load in structure design.

A Discussion on recent research in air pollution - The dispersion of pollutants in the free atmosphere by the large scale wind systems

1969 ◽  
Vol 265 (1161) ◽  
pp. 273-294 ◽  
Keyword(s):  
Wind Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Horizontal Wind ◽  
Wind Fields ◽  
Free Atmosphere ◽  
Mean Values ◽  
Level Model ◽  
Small Factor ◽  
Numerical Forecast

The travel and dispersion of pollutants in the free atmosphere m ay be investigated by the direct measurement of the distributions of tracer materials such as water vapour, ozone and radioactive substances. Another method is to study the spread of pollutants from a constant point source or the expansion of large clusters, by using air trajectories found by tracking balloons or estimated from sequences of wind values obtained from synoptic charts. So far these latter techniques have usually only taken horizontal motions into account since the balloons are normally maintained at constant levels and the winds taken from the charts have been assumed to be geostrophic. In principle the effect of large (synoptic) scale vertical motions can be included by using the component wind fields given at the different time steps of a numerical forecast integration to construct suitable three-dimensional trajectories. A pilot study of this type at the 900, 700, 500 and 300 m bar pressure levels (90, 70, 50 and 30kN m ~2) using the results of a 24 h numerical forecast by the Meteorological Office’s 10 level model is described. In the case studied the use of constant level trajectories gave horizontal dispersions (variances of the trajectory end points relative to their centre of gravity) which differed by only small amounts from those due to the three dimensional trajectories. The zonal variances exceeded the meridional variances by a small factor and both were 4 to 6 orders greater than those of the corresponding variances in the vertical. In each case for at least 12 to 18 h they were all roughly proportional to the square of the time after release (the ‘short time’ case). The large scale clusters rapidly distorted at rates which increased with their initial size and also with the deformation components of the wind field. At these scales deformation plays a major role in the apparent dispersion and the mean values of total deformation so obtained agreed satisfactorily with those calculated from a kinematic analysis of the horizontal wind field.

scholarly journals Reconstruction of Three-Dimensional Dynamic Wind-Turbine Wake Wind Fields with Volumetric Long-Range Wind Doppler LiDAR Measurements

2019 ◽  
Vol 11 (22) ◽  
pp. 2665 ◽  
Author(s):  
Beck ◽  
Kühn
Keyword(s):  
Wind Turbine ◽  
Long Range ◽  
Wind Field ◽  
Three Dimensional ◽  
Wake Flow ◽  
Wind Fields ◽  
Wake Field ◽  
Eddy Simulation ◽  
Lidar Measurements ◽  
Set Up

This paper presents a method for reconstructing the wake wind field of a wind turbine based on planar light detection and ranging (LiDAR) scans crossing the wake transversally in the vertical and horizontal directions. Volumetric measurements enable the study of wake characteristics in these two directions. Due to a lack of highly resolved wind speed measurements as reference data, we evaluate the reconstruction in a synthetic environment and determine the reconstruction errors. The wake flow of a multi-megawatt wind turbine is calculated within a 10-min large-eddy simulation (LES) for high-thrust loading conditions. We apply a numerical LiDAR simulator to this wake wind field to achieve realistic one-dimensional velocity data. We perform a nacelle-based set-up with combined plan position indicator and range height indicator scans with eight scanning velocities each. We temporally up-sample the synthetic LiDAR data with a weighted combination of forward- and backward-oriented space–time conversion to retrospectively extract high-resolution wake characteristic dynamics. These dynamics are used to create a dynamic volumetric wake deficit. Finally, we reconstruct the dynamic wake wind field in three spatial dimensions by superposing an ambient wind field with the dynamic volumetric wake deficit. These results demonstrate the feasibility of wake field reconstruction using long-range LiDAR measurements.

scholarly journals Fabrication of Eutectic Ga-In Nanowire Arrays Based on Plateau–Rayleigh Instability

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4616
Author(s):  
Takashi Ikuno ◽  
Zen Somei
Keyword(s):  
Integrated Circuits ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Scanning Probe ◽  
Rayleigh Instability ◽  
Simple Method ◽  
Flat Substrate ◽  
Metal Nanowire

We have developed a simple method of fabricating liquid metal nanowire (NW) arrays of eutectic GaIn (EGaIn). When an EGaIn droplet anchored on a flat substrate is pulled perpendicular to the substrate surface at room temperature, an hourglass shaped EGaIn is formed. At the neck of the shape, based on the Plateau–Rayleigh instability, the EGaIn bridge with periodically varying thicknesses is formed. Finally, the bridge is broken down by additional pulling. Then, EGaIn NW is formed at the surface of the breakpoint. In addition, EGaIn NW arrays are found to be fabricated by pulling multiple EGaIn droplets on a substrate simultaneously. The average diameter of the obtained NW was approximately 0.6 μm and the length of the NW depended on the amount of droplet anchored on the substrate. The EGaIn NWs fabricated in this study may be used for three-dimensional wiring for integrated circuits, the tips of scanning probe microscopes, and field electron emission arrays.

Dynamic simulation of wind field in three-dimensional display space considering particle swarm algorithm fuzzy logic

2021 ◽  
pp. 1-6
Author(s):  
Honglei Xu ◽  
Linhuan Wang
Keyword(s):  
Fuzzy Logic ◽  
Dynamic Simulation ◽  
Wind Field ◽  
Three Dimensional ◽  
Measurement Data ◽  
Particle Swarm ◽  
Particle Swarm Algorithm ◽  
Three Dimensional Display ◽  
Swarm Algorithm ◽  
Synchronous Measurement

In order to improve the accuracy of dynamic detection of wind field in the three-dimensional display space, system software is carried out on the actual scene and corresponding airborne radar observation information data, and the particle swarm algorithm fuzzy logic algorithm is introduced into the wind field dynamic simulation process in three-dimensional display space, to analyze the error of the filtering result in detail, to process the hurricane Lily Doppler radar measurement data with the optimal adaptive filtering according to the error data. The three-dimensional wind field synchronous measurement data obtained by filtering was compared with three-dimensional wind field synchronous measurement data of the GPS dropsonde in this experiment, the sea surface wind field measurement data of the multi-band microwave radiometer, and the wind field data at aircraft altitude.

scholarly journals The ICON Single-Column Mode

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 906
Author(s):  
Ivan Bašták Ďurán ◽  
Martin Köhler ◽  
Astrid Eichhorn-Müller ◽  
Vera Maurer ◽  
Juerg Schmidli ◽  
...  
Keyword(s):  
Data Storage ◽  
Model Development ◽  
Computational Cost ◽  
Three Dimensional ◽  
Shallow Convection ◽  
Modeling Framework ◽  
Additional Tool ◽  
Eddy Simulation ◽  
Single Column ◽  
Stratocumulus Clouds

The single-column mode (SCM) of the ICON (ICOsahedral Nonhydrostatic) modeling framework is presented. The primary purpose of the ICON SCM is to use it as a tool for research, model evaluation and development. Thanks to the simplified geometry of the ICON SCM, various aspects of the ICON model, in particular the model physics, can be studied in a well-controlled environment. Additionally, the ICON SCM has a reduced computational cost and a low data storage demand. The ICON SCM can be utilized for idealized cases—several well-established cases are already included—or for semi-realistic cases based on analyses or model forecasts. As the case setup is defined by a single NetCDF file, new cases can be prepared easily by the modification of this file. We demonstrate the usage of the ICON SCM for different idealized cases such as shallow convection, stratocumulus clouds, and radiative transfer. Additionally, the ICON SCM is tested for a semi-realistic case together with an equivalent three-dimensional setup and the large eddy simulation mode of ICON. Such consistent comparisons across the hierarchy of ICON configurations are very helpful for model development. The ICON SCM will be implemented into the operational ICON model and will serve as an additional tool for advancing the development of the ICON model.

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