Effect Of Wind Direction Research Articles

The effect of lunar cycle, tidal condition and wind direction on the catches and profitability of Japanese common squid Todarodes pacificus jigging and trap-net fishing

Jigging with artificial lights (squid jigging) and deploying of large scale trap-net (also known as a set-net in Japan), are the major methods to capture Japanese common squid Todarodes pacificus in western Japan. Squid jigging is a highly selective fishing method. However, it consumes large amount of energy for steaming to the fishing ground and for lighting. In contrast, trap-net fishing requires substantially less energy but its capture efficiency is strongly influenced by its stationary mode of capture. The primary objective of this study was to analyze how various environmental and biological factors such as the lunar cycle, tidal condition, wind direction and squid abundance affect the capture efficiency of squid jigging and trap-net fishing. We analyzed the effect of these factors on squid catch in five Fisheries Cooperative Associations located on four islands in Nagasaki Prefecture, western Japan. Our analysis shows that squid catch in jigging and trap-net fishing is mainly influenced by the lunar cycle but also tide and wind direction play a marked role. In addition, squid abundance significantly affects the catches in trap-net fishing. Recommendations are made to improve the overall profitability of squid fishing by proper choice of the capture method, location and season.

Opening window issue of residential buildings in winter in north China: A case study in Shenyang

Mechanical ventilation systems aren’t installed in most residential buildings in north China and the residents generally rely on opening windows to improve the indoor air quality. Heat loses drastically in minutes of natural ventilation due to great indoor and outdoor temperature difference in winter. A winter survey, including 500 random subjects interviewed face to face, was conducted in Shenyang aiming to present the opening window status of the residents, ascertain the features of indoor thermal sensation, house area, storey number, time at home, household number, feeling of indoor air quality and health consciousness and reflections of these features on the opening window habit. Furthermore, a winter test of air change rate (ACR) of opening windows, which is positively correlated to heat loss, was conducted in rooms of different sizes of a typical residential building. According to the analysis based on Chi-square (χ2) test, subjective feeling of indoor air quality and personal health consciousness were found to be significantly correlated with residents’ opening window habit. In the case of Shenyang, some rules of the effect of room size, wind direction and window opening size on ACR in winter were discovered and a few suggestions on people's opening window habit were provided.

Erratum to: Relative Importance of Nutrient Load and Wind on Regulating Interannual Summer Hypoxia in the Chesapeake Bay

To analyze the correlations of summer anoxia/hypoxia in the Chesapeake Bay with watershed input and wind conditions, statistics were applied to nearly three decades of monitoring data. The results of Pearson correlation coefficients, multivariate regression analysis, and cluster analysis indicate that anoxia/hypoxia has a strong positive correlation with nutrient load and a moderate negative correlation with wind speed. Physical relationships among the relevant constituents were analyzed. Nutrient loads and the subsequent decay of organic matter are the primary factors that control the oxygen demand causing summer anoxia and hypoxia, while episodic wind can partially erode stratification and reduce anoxia/hypoxia. Although the extent of anoxia/hypoxia reduction differs with wind direction, higher wind speeds result in more destratification and anoxia/hypoxia reduction than lower wind speeds and are more important than the effect of wind direction. The influences of freshwater discharge, stratification, and temperature were also analyzed. Computer modeling results were used to obtain dissolved oxygen conditions at finer temporal and spatial scales to supplement the scattered and discrete observations from monitoring stations and for better understanding of anoxia/hypoxia development under episodic wind events.

Relative Importance of Nutrient Load and Wind on Regulating Interannual Summer Hypoxia in the Chesapeake Bay

To analyze the correlations of summer anoxia/hypoxia in the Chesapeake Bay with watershed input and wind conditions, statistics were applied to nearly three decades of monitoring data. The results of Pearson correlation coefficients, multivariate regression analysis, and cluster analysis indicate that anoxia/hypoxia has a strong positive correlation with nutrient load and a moderate negative correlation with wind speed. Physical relationships among the relevant constituents were analyzed. Nutrient loads and the subsequent decay of organic matter are the primary factors that control the oxygen demand causing summer anoxia and hypoxia, while episodic wind can partially erode stratification and reduce anoxia/hypoxia. Although the extent of anoxia/hypoxia reduction differs with wind direction, higher wind speeds result in more destratification and anoxia/hypoxia reduction than lower wind speeds and are more important than the effect of wind direction. The influences of freshwater discharge, stratification, and temperature were also analyzed. Computer modeling results were used to obtain dissolved oxygen conditions at finer temporal and spatial scales to supplement the scattered and discrete observations from monitoring stations and for better understanding of anoxia/hypoxia development under episodic wind events.

Large Scale Diesel Oil Burns

Diesel oil was burnt in a 41.5 m diameter real oil storage tank. Thermal radiation and IR–image of the flame were obtained. Effects of wind direction for external thermal radiation were studied. Results of thermal radiation and IR–image are in good agreement with our previous results, and justified our previous results in large scale tanks, up to 50 m in diameter which were burnt on the ground.

Observations of the site dependency of the morning wind and the role of gravity waves in the transitions

Values of 10 m wind speed have been plotted against screen temperature during morning warming and averaged over several years for a number of sites within Great Britain. When the temperature is referenced to that at the time of the coming evening transition the plots give consistent lines with a gradient dependent on geostrophic wind. However the gradient for a given geostrophic wind varies between sites. Comparison with similar plots made during evening cooling shows that the wind plot against temperature increases relatively abruptly at some stage during the early hours of the morning and then increases to its midday maximum with a reduced wind–temperature gradient to that in the evening. However, as with the evening plots, the gradients of the morning plots increase in hillier terrain. The effect of wind direction on the gradients during morning and evening is also described in order to verify that the effect of topography on the plots is consistent. A one‐dimensional numerical model is used to simulate both transitions. It is shown that external drag factors such as form drag in the region of low hills are not sufficient to explain the observations. Only an external drag of the type given by a simple formulation of gravity wave generation and absorption within the stable boundary layer gives good agreement with the observations. This suggests that an important factor causing the wind to drop during the evening cooling is gravity wave drag and its relative absence, due to the near‐surface convective layer, is a factor during the morning wind increase.

Effects of Lateral Window Position and Wind Direction on Wind-Driven Natural Cross Ventilation of a Building: A Computational Approach

Energy is saved when an effective natural ventilation system can provide comfort air to the occupants in a building by replacing a mechanical ventilation system. It also minimizes the risk of the environmental pollution and the global warming. A one story, full scale building was considered to carry out a comparative study of three different cases of wind-driven natural (WDN) cross ventilation with the help of computational fluid dynamics (CFD). In each case, the location of window was changed in lateral direction to predict the probable position for optimum ventilation performance and the angle of wind was varied to check the sensitivity of the wind direction on the flow field. After validating the current methodology through two satisfactory comparisons with the experimental investigations, the governing equations subjected to the corresponding boundary conditions were solved using commercial software and then the results were analyzed. A better location for the windows in each case was proposed. The ventilation purpose was served quite well even if the wind angle was changed in a moderate range from the original design. Furthermore, the velocity components, ventilation rate, surface pressure, ventilation time, and so forth in each case were investigated and compared extensively with those in other cases.

Spatio-temporal analysis of the relationship between LST from MODIS and air temperature in New Zealand

The ambient air temperature (Ta) is an important environmental parameter which can be estimated from satellite observations of the land surface temperature (LST) using a linear regression model. This paper attempts to answer the question of whether the series of a single pixel or a spatially averaged series over several pixels should be used for modelling Ta from remotely sensed LST data. Sensitivity of LST-Ta relationship to the moderate resolution imaging spectroradiometer (MODIS) window size, which determines the number of pixels contributed in the correlations, over a number of test sites in New Zealand was analysed. LST series of a single pixel over a period of 10 years gave a correlation coefficient $r\geqslant $ 0.80 with Ta measurements. Bootstrapping by random resampling from seasonal subsets of both time-series was applied to determine seasonal and inter-annual variability of LST-Ta relationship. A fast Fourier filtering was applied for noise reduction and detection of dominant spectra in LST series. Spatially averaged time-series from larger windows, which included more pixels, showed slightly higher agreement with Ta measurements. We considered the effects of wind speed (WS) and wind direction (WD) on the LST-Ta relationship. Highest correlation between Ta and LST time-series was achieved using a 25 × 25 window at 2 ≤ WS < 8 ms−1. No significant effect due to WD was found in the results. MODIS-Terra nighttime (∼10:30 PM) observations showed the highestwhile MODIS-Aqua nighttime (∼1:30 AM) observations showed the lowest agreement with Ta measurements. These results indicate that the best approach for modelling Ta based on LST observations from MODIS in the long-term is to use a spatially averaged LST series over a window of 5 × 5 to 25 × 25 pixels, with a consideration of WS effects and observation times.

Circular Circular – Linear Regression Analysis of Order m in Circular Variable α and β against Linear Variable (Y)

The development of data analysis is still predominanlty use linear statistics. Whereas the research world there are other types of data is data direction. One type of data direction is the data circular. Statistical analysis aimed at modeling the causal relationship between the independent variable and the dependent variable is regression analysis. So as to model the relationship between wind direction and cloud direction against rainfall is circular circular - linear multiple regression analysis. The purpose of this research it to build a model circular circular - linear regression analysis of order m in circular variable α and β against linear variable (Y). Data used in this research is the simulation data and secondary data obtained from the Meteorology, Climatology, and Geophysics in Bogor a cityof West Java, Indonesia. The data is the result of observations of wind direction, coulds direction, and rainfall in february 2014 and march 2014. From the analysis of the data showed that the best model to see the effect of wind direction and could direction against rainfall is circular circular - linear regression analysis to the order four better of the linear multiple regression analysis. It is seen from the sum square of error, p-value, and r-square.

Correlation and combination of wind force components and responses

This paper summarizes the findings from extensive wind tunnel tests carried out by the authors' group for the evaluation of wind load combination effects for various types of building models. Characteristics of correlations of wind force components are examined using the absolute ratio of wind forces, phase–plane trajectories and (absolute) cross-correlation, and then wind load combinations are examined. The necessity to consider wind load combinations is inferred from the instantaneous pressure distributions, and the cross-correlation coefficients of the absolute values of wind force components are found to be more important when examining wind force combinations. Wind load combination effects are directly examined using frame models. Based on the peak normal stresses in columns under various loading conditions, combination factors for low-, middle- and high-rise buildings are proposed. Lastly, effects of wind direction on wind load combinations are discussed.

Experimental Investigation and Theoretical Analysis on Galloping of Iced Conductors

The aerodynamic forces of two typical iced conductor models are obtained by high frequency balance technique in wind tunnel test. The effects of wind directions and turbulence intensity on aerodynamic forces coefficients are discussed. An analytical expression for predicting the galloping instability trends in arbitrary directions is derived. An aerodynamic model considering the dynamic swing is developed according to the quasi-steady theory. Galerkins procedure is employed to discrete the governing equations of transmission line, which is modeled as a suspended homogeneous elastic cable having a small equilibrium curvature and neglecting the shear deformation. The forth order Runge-Kutta method are applied to obtained the approximate numerical results of iced transmission line galloping.

The effect of wind direction on flying fish counts

Flying fish and squid flushed by a ship's passage are easy to count, but the value of such data is compromised by uncertainty regarding the proportion of individuals flushed. Wind direction relative to the ship's course plays an important role in determining this proportion, with on average 6 times (range 2.5–10.8) more fish flushed on the windward side of the ship when there are moderate to strong cross winds. As a result, counts of flying fish that cover only one side of a ship's bow should sample the windward side.

Numerical investigation of VOC levels in the area of petrol stations

In the area of petrol stations several Volatile Organic Compounds (VOCs) leak into the atmosphere due to the evaporation of liquid fuels, especially of gasoline that is predominantly composed of light hydrocarbons. The aim of the present study is to investigate the spatial distribution of various VOCs when leaked into the atmosphere in the area of a petrol station. The study is based on numerical simulations. The effect of wind speed and direction, as well as of air temperature has been studied. Gasoline components of different properties have been studied (e.g. pentane, iso-octane, o-xylene, toluene, benzene), as well as ethanol that is considered a new fuel blend component that can be found in different fractions in new gasoline blends worldwide. The area of flammable cloud near the source of the leak is investigated for various atmospheric conditions taking into account the lower and higher flammable limits of each compound. Lastly, the exposure to gasoline vapour is studied taking into consideration the recommended occupational exposure limits of various organisations.

Effect of wind direction on the response and capacity surface of a transmission tower

Electrical transmission structures play a vital role in power transmission networks throughout the world and are often subject to strong wind loads. The present study investigates the inelastic response of a self-supported lattice transmission tower under different wind events, including traditional atmospheric boundary layer wind (ABL) and downburst wind, and for wind loading at different directions relative to the tower. The nonlinear static pushover (NSP) analysis is used to obtain the capacity curve of the tower, defined by the force–deformation relationship, at each considered wind direction. The results show that the yield and maximum capacities vary with wind direction. The deformation trajectory is projected on the horizontal plan for each wind direction, illustrating the out-of-plane loading deformation. Since the trajectories are sufficiently smooth and do not overlap for closely spaced wind directions, it is suggested that the capacity curves obtained for different wind directions can be used to form the capacity surface of the tower. Moreover, the results indicate that the capacity for ABL and rectangular (uniform) winds could provide an approximate envelope for the capacity estimated for different sizes of downburst events. These findings could assist in the evaluation of the adequacy of existing towers under downburst events, as well as in the design of new towers.

A Numerical Study of the Effects of Wind Direction on Turbine Wakes and Power Losses in a Large Wind Farm

In this study, large-eddy simulations (LESs) were performed to investigate the effects of changing wind direction on the turbine wakes and associated power losses in the Horns Rev offshore wind farm. In the LES framework, the turbulent subgrid-scale stresses are parameterized using a tuning-free Lagrangian scale-dependent dynamic model, and the turbine-induced forces are computed using a dynamic actuator-disk model with rotation (ADM-R). This dynamic ADM-R couples blade-element theory with a turbine-specific relation between the blade angular velocity and the shaft torque to compute simultaneously turbine angular velocity and power output. A total of 67 simulations were performed for a wide range of wind direction angles. Results from the simulations show a strong impact of wind direction on the spatial distribution of turbine-wake characteristics, such as velocity deficit and turbulence intensity. This can be explained by the fact that changing the wind angle can be viewed as changing the wind farm layout relative to the incoming wind, while keeping the same wind turbine density. Of particular importance is the effect of wind direction on the distance available for the wakes to recover and expand before encountering other downwind turbines (in full-wake or partial-wake interactions), which affects the power losses from those turbines. As a result, even small changes in wind direction angle can have strong impacts on the total wind farm power output. For example, a change in wind direction of just 10° from the worst-case full-wake condition is found to increase the total power output by as much as 43%. This has important implications for the design of wind farms and the management of the temporal variability of their power output.

Space-Based GNSS Scatterometry: Ocean Wind Sensing Using an Empirically Calibrated Model

This paper presents a method and experimental results for near-surface wind sensing using reflected Global Navigation Satellite Systems (GNSS) signals received on a spacecraft. The estimation method proposed involves four steps. First, the bistatic radar cross section (BRCS) of the received signal is estimated from the measurements. Second, the BRCS measurements are calibrated to agree with existing theoretical and empirical wind-wave models. Next, a geometric optics-based scattering model is used to estimate the sea surface slopes, based on the reflection geometry and the measured BRCS. Finally, the surface winds are estimated using an empirically derived function relating the surface mean square slopes to near-surface wind speed. The accuracy of the proposed inversion technique is then tested using a set of 25 space-based GNSS reflection measurements over a range of wind speeds. These measurements were all taken in the proximity of ocean buoys which provided in situ ocean wind speed information. The wind estimates from the buoys were then compared with the wind retrievals made from the measurements and found to be accurate to a root-mean-square error of 1.84 m/s. Additionally, the potential error sources in the measurements are analyzed, including a simulation of the effects of wind direction on the BRCS measurements. This first demonstration of space-based GNSS scatterometry using a small set of sample measurements will hopefully provide a benchmark and example for future experiments.

Using Data From Seed-Dispersal Modelling to Manage Invasive Tree Species: The Example of Fraxinus pennsylvanica Marshall in Europe

Management strategies to control invasive species need information about dispersal distances to predict establishment potential. Fraxinus pennsylvanica is a North American anemochorous tree species that is invasive in many Central European floodplain forests. To predict seed-dispersal potential, the stochastic model WaldStat was used, which enables different options for directionality (isotropic and anisotropic) to be simulated. In this article, we (1) show empirical results of fructification and seed dispersal for this tree species. The model predicts approximately 250,000 seeds for one F. pennsylvanica tree. These results were used to (2) calculate species-specific dispersal distances and effects of wind direction. To consider the influence of wind on dispersal potential of the tree species, long-distance dispersal (LDD [95th percentile dispersal distance]) was calculated. Mean dispersal distances varied between 47 and 66m. LDD values modelled along the main wind direction ranged from 60 to 150m. Seed production, dispersal distance, and direction data were (3) incorporated into theoretical management scenarios for forest ecosystems. Finally (4), we discuss management options and the practical relevance of model scenarios in relation to the accuracy of spatial dispersal predictions. Further analyses should be focused on possible, well-adapted management concepts at stand level that could restrict the potential spread of invasive species.

The Effects of Environment Wind on Heat Transfer Performance of Direct Air Cooled Island and its Improvements

Using a CFD software, the numerical simulation of a 2×300MW direct air-cooled unit is done by multi-stage modeling method. the effect of the environmental wind on the heat-exchanging performance of the air-cooling island is analyzed by numerical simulation. The effects of different wind velocities and directions on exterior flow field and heat-exchanging efficiency are analyzed. The reasons of hot air recirculation and the decrease of the fans’ output are found. The heat transfer performance of air-cooled island is affected after the installation of windproof net. The result shows that the form of low-pressure area is the main reason for the hot air reflow and the decreace of the fan’s output; An improved flow field can be got after installing the windproof net. The volumetric effectiveness can be increased by 8.5% at a wind speed of 9 m/s.

Spatial–temporal variations of particle number concentrations between a busy street and the urban background

To estimate spatial–temporal variations of ultrafine particles (UFP) in Helsinki, we measured particle total number concentrations (PNC) continuously in a busy street and an urban background site for six months, using condensation particle counters (CPC). We also evaluated the effects of temperature, wind speed and wind direction on PNC, as well as the correlation between PNC and PM2.5, PM10 and black carbon (BC) at the street. We found that on weekdays, hourly median PNC were highly correlated with BC (r = 0.88), moderately correlated with PM2.5 (r = 0.59) and weakly correlated with PM10 (r = 0.22). Number concentrations at the street were inversely proportional to temperature and wind speed, and highly dependent on wind direction. The highest PNC occurred during northeastern winds while the lowest occurred during southwestern winds. As these wind directions are nearly perpendicular to the street axis, the formation of wind vortices may have influenced the dispersion of UFP in the site. Although the temporal correlation for PNC was moderately high between the sites (r = 0.71), the median concentration at the street was 3 times higher than the urban background levels. The results indicate that people living or passing by the busy street are exposed to UFP concentrations well above the urban background levels. Thus, the study suggests that urban microenvironments should be considered in epidemiological studies. In addition the results emphasize that regulations based solely on PM2.5 and PM10 concentrations may be insufficient for preventing the adverse health effects of airborne particles.

Effects of oblique air flow on burning rates of square ethanol pool fires

The effects of downward airflow on the burning rate and/or burning intensity of square alcohol pool fires for different airflow speeds and directions have been studied experimentally in an inclined wind tunnel. An interesting flame-wrapping phenomenon, caused by impingement of air flow, was observed. The mass burning intensity was found to increase with the airflow speed and the impinging angle. The fuel pan rim temperatures were also measured to study the effect of wind direction and speed on heat transfer from the flame to the fuel source. A model based on heat transfer analysis was developed to correlate the burning intensity with the pan rim characteristic temperature. A good correlation was established between the model results and the experimental results.