A Novel Estimation Method of Wind Speed and Direction Based on GNSS/INS/ADS Integrated Navigation

Arriving on time is of great importance for flight management and passenger experience. One of the essential factors that impacts on-time arrival is the wind condition. Accurate information of wind speed and direction around the fuselage helps to improve the performance of on-time arrival and four-dimensional trajectory (4DT) planning. To determine accurate wind information in real-time, a novel airborne estimation method of wind speed and direction is proposed in this paper. Inertial Navigation System (INS), Global Satellite Navigation System (GNSS), and Air Data System (ADS) are fused in an Unscented Kalman Filter (UKF), which provides great accuracy and robustness in nonlinearity conditions. The dynamic models of wind are established, and implementations of the UKF are detailed. Finally, simulations are designed and the effectiveness of the proposed method is verified through the comparison with the traditional direct measurement method. Results demonstrate that the accuracy of wind speed and direction obtained by our method is nearly two times higher than the traditional direct measurement method.

Effects of the Solar Wind Dynamic Pressure on the Martian Topside Ion Distribution: Implications on the Variability of Bulk Ion Outflow

With the aid of the ion densities measured by the Neutral Gas and Ion Mass Spectrometer and the solar wind dynamic pressures measured by the Solar Wind Ion Analyzer on board the Mars Atmosphere and Volatile EvolutioN, we investigate the modulation of a sequence of ion species in the Martian topside ionosphere by the upstream solar wind condition. Almost all ion species, except for CO 2 + and OCOH+, are very sensitive to the variation of the solar wind condition, and their densities decrease with increasing solar wind dynamic pressure. The response of the topside ion distribution to the variation of the solar wind condition is also found to be remarkably related to the magnetic field orientation, in that the solar wind modulation occurs mainly over regions with near-horizontal field lines. These observations imply substantially enhanced outflow velocities for all ion species under high solar wind dynamic pressures when the ambient magnetic fields are near-horizontal.

A new three-dimensional wake model for the real wind farm layout optimization

The utilization of wind energy has attracted extensive attentions in the last few decades around the world, providing a sustainable and clean source to generate electricity. It is a common phenomenon of wake interference among wind turbines and hence the optimization of wind farm layout is of great importance to improve the wind turbine yields. More specifically, the accuracy of the three-dimensional wake model is critical to the optiamal design of a real wind farm layout considering the combinatorial effect of wind turbine interaction and topography. In this paper, a novel learning-based three-dimensional wake model is proposed and subsequently validated by comparison to the high-fidelity wake simulation results. Moreover, due to the fact that the inevitable deviation of actual wind scenario from the anticipated one can greatly jeopardize the wind farm optimization outcome, the inaccuracy of wind condition prediction using the existing meteorologic data with limited-time measurement is incorporated into the optimization study. Different scenarios including short-, medium-, and long-term wind data are studied specifically with the wind speed/direction prediction errors of [Formula: see text] 0.25 m/s, [Formula: see text] 5.62 [Formula: see text], [Formula: see text] 0.08 m/s, [Formula: see text] 1.75 [Formula: see text] and [Formula: see text] 0.025 m/s, [Formula: see text] 0.56 [Formula: see text], respectively. An advanced objective function which simultaneously maximizes the power output and minimizes the power variance is employed for the optimization study. Through comparison, it is found that the optimized wind farm layout yields over 210 kW more total power output on average than the existed wind farm layout, which verifies the effectiveness of the wind farm layout optimization tool. The results show that as the measurement time for predicting the wind condition gets longer, the total wind farm power output average increases while the error of power output prediction decreases. For the wind farm with 20 wind turbines installed, the individual power output is above 500 kW with an error of 90 kW under the short-term wind [Formula: see text] 0.25 m/s, [Formula: see text] 5.62 [Formula: see text], while it is above 530 kW with an error of 10 kW under the long-term wind [Formula: see text] 0.025 m/s, [Formula: see text] 0.56 [Formula: see text].

Microscale and Mesoscale Aeolian Processes of Sandy Coastal Foredunes from Background to Extreme Conditions

Aeolian transport affects beach and foredune pre-storm morphologies, which directly contribute to storm responses. However, significant spatiotemporal variation exists within beach-dune systems regarding how biotic and abiotic factors affect topography. There are multiple metrics for quantifying topographic change, with varying pros and cons, but understanding how a system changes across spatiotemporal scales relative to varying forcings is necessary to accurately model and more effectively manage these systems. Beach and foredune micro- and mesoscale elevation changes (Δz) were quantified remotely and in situ across a mid-Atlantic coastal system. The microscale field collections consisted of 27 repeat measurements of 73 elevation pins located in vegetated, transitional, and unvegetated foredune microhabitats over three years (2015 to 2018) during seasonal, event-based, and background wind-condition collections. Unoccupied aerial System (UAS) surveys were collected to link microscale point Δz to mesoscale topographic change. Microscale measurements highlight how Δz varies more pre- to post-event than seasonally or monthly, but regardless of collection type (i.e., seasonal, monthly, or event-based), there was lower Δz in the vegetated areas than in the associated unvegetated and partially vegetated microhabitats. Despite lower Δz values per pin measurement, over the study duration, vegetated pins had a net elevation increase of ≈20 cm, whereas transitional and unvegetated microhabitats had much lower change, near-zero net gain. These results support vegetated microhabitats being more stable and having better sediment retention than unvegetated and transitional areas. Comparatively, mesoscale UAS surfaces typically overestimated Δz, such that variation stemming from vegetation across microhabitats was obscured. However, these data highlight larger mesoscale habitat impacts that cannot be determined from point measurements regarding volumetric change and feature mapping. Changes in features, such as beach access paths, that are associated with increased dynamism are quantifiable using mesoscale remote sensing methods rather than microscale methods. Regardless of the metric, maintaining baseline data is critical for assessing what is captured and missed across spatiotemporal scales and is necessary for understanding the contributors to heterogeneous topographic change in sandy coastal foredunes.

Investigation of sea spray effect on the vertical momentum transport using an Eulerian multi-fluid-type model

The Eulerian multi-fluid mathematical model is developed to describe the marine atmospheric boundary layer laden with sea spray under high wind condition of a hurricane. The model considers spray and air as separate continuous interacting turbulent media and employs the multi-fluid E – ε closure. Each phase is described by its own set of coupled conservation equations and characterized by its own velocity. Such an approach enables us to accurately quantify the interaction between spray and air and pinpoint the effect of spray on the vertical momentum transport much more precisely than could be done with traditional mixture-type approaches. The model consistently quantifies the effect of spray inertia and the suppression of air turbulence due to two different mechanisms: the turbulence attenuation, which results from the inability of spray droplets to fully follow turbulent fluctuations, and the vertical transport of spray against the gravity by turbulent eddies. The results of numerical and asymptotic analyses show that the turbulence suppression by spray overpowers its inertia several meters above wave crests resulting in a noticeable wind acceleration and the corresponding reduction of the drag coefficient from the reference values for a spray-free atmosphere. This occurs at a much lower than predicted previously spray volume fraction values ~ 10−5. The falloff of the drag coefficient from its reference values is stronger pronounced at higher altitudes. The drag coefficient reaches its maximum at spray volume fraction values ~ 10−4 that is several times smaller than predicted by mixture-type models.

Experimental Study of the Skin-Friction Topology Around the Ahmed Body in Cross-Wind Conditions

In this study, skin friction around a ½-scale Ahmed body was measured experimentally at a Reynolds number of Re = 2×105. The slant angle of the Ahmed body was 25° and the yaw angles ranged from 0° to 8°. This study focused on the flow structure on the slant surface under different cross-wind conditions. A force balance system was applied to measure the aerodynamic drag of the model. The global skin-friction topology was measured by applying a luminescent oil layer with a sub-grid data processing algorithm. The method used to measure the skin friction was conducted for the first time on the Ahmed body. The results indicated that the technique is highly capable of extracting the skin-friction topology. For a yaw angle below 3°, the flow on the slant surface was not significantly affected by the cross-wind condition and the drag of the model was nearly constant. However, at yaw angles above 3°, the flow on the slant surface was highly affected by the roof longitudinal vortexes on the windward side, leading to a dramatic increase in the drag of the model. High consistency in the drag and skin-friction fields was observed. The detailed skin-friction structure at different yaw angles will be discussed in this study.

Quadrangle Courtyard Green Simulation Approach to Renovation of Residential Buildings in China

<p><b>Development of technology and the rapid increase in population has led to tremendous growth in the population of China. Beijing the capital city has become significantly overcrowded due to a high number of residents.The traditional courtyard houses have been drastically transformed and lost their cultural values over time. The quadrangle courtyard reflects the work and art of conventional Chinese residences. An average Beijing quadrangle courtyard building reflects both utility and aesthetics in its design and development. Quadrangle courtyard is designed to have a family-centered pattern with neighbors of the trunk and the community area for social networking and finally denotes cultural profundity. The poor architectural designs and ineffective construction practices have caused many problems in the city regarding sustainability and environmental protection, which has, in turn, increased the concerns of people towards building the traditional houses to ensure better living standards and greater sustainability. This study aims to conduct an evaluation of applications of green construction practices of the traditional courtyard houses on the renovation and reconstruction of contemporary residential buildings in Beijing. </b></p> <p>The study utilizes quantitative approaches for collection and subsequent evaluation of data regarding the subject matter of the research. With respect to the literature review, thesis has performed a review of different literature including journal articles, books, newspapers, and other publications, while for collection of primary data has used with computer-assisted architectural simulation models, which is then analyzed through data triangulation technique. Further, a base model and reference models are generated for computer simulation usingPhoniecs and Green Simulation Studio software's, for the analysis and to analyse the influence of internal courtyard and courtyard for wind flow. The model that exhibits the best width to length ratio and natural room environment is chosen for evaluation.The study was conducted in the residential areas of Dashilar Hutong, Jingyang, Deyang,Dongcheng District, Yue Hutong, Changchun Street Hutong Area, and Yongning District. The study is limited to the given areas only, and no evaluation is performed on other areas of the city and buildings that are not recently renovated or reconstructed. The study also provides recommendations to the architect firms and regulatory authorities regarding applications of green construction practices of the traditional courtyard houses on the renovation and reconstruction of contemporary residential buildings in Beijing. In the assessment, the spatial design of courtyards is balanced; the aspect ratio is planned to crate natural buffer space is created.</p> <p>Further, to examine the performance of the courtyard design the study applied the Computational Fluid Dynamics (C.F.D.) programming, Parabolic Hyperbolic, or Elliptic Numerical Integration Code Series (PHOENICS), for wind condition simulation. Later with the help of the Green build studio of Autodesk, the study had undergone Green Simulation. The Quadrangle courtyard building performance is analyzed by Green BuildingStudio to generate outputs like heating and cooling loads, and monthly electricity and fuel consumption, and their life cycle cost. Results show for a courtyard with a decent combination of courtyard layout and aspect ratiois chosen. Finally, the study suggests the best suited planning strategy for the new proposals and design implications for a new courtyard from the angle of green building construction.</p>

Quadrangle Courtyard Green Simulation Approach to Renovation of Residential Buildings in China

<p><b>Development of technology and the rapid increase in population has led to tremendous growth in the population of China. Beijing the capital city has become significantly overcrowded due to a high number of residents.The traditional courtyard houses have been drastically transformed and lost their cultural values over time. The quadrangle courtyard reflects the work and art of conventional Chinese residences. An average Beijing quadrangle courtyard building reflects both utility and aesthetics in its design and development. Quadrangle courtyard is designed to have a family-centered pattern with neighbors of the trunk and the community area for social networking and finally denotes cultural profundity. The poor architectural designs and ineffective construction practices have caused many problems in the city regarding sustainability and environmental protection, which has, in turn, increased the concerns of people towards building the traditional houses to ensure better living standards and greater sustainability. This study aims to conduct an evaluation of applications of green construction practices of the traditional courtyard houses on the renovation and reconstruction of contemporary residential buildings in Beijing. </b></p> <p>The study utilizes quantitative approaches for collection and subsequent evaluation of data regarding the subject matter of the research. With respect to the literature review, thesis has performed a review of different literature including journal articles, books, newspapers, and other publications, while for collection of primary data has used with computer-assisted architectural simulation models, which is then analyzed through data triangulation technique. Further, a base model and reference models are generated for computer simulation usingPhoniecs and Green Simulation Studio software's, for the analysis and to analyse the influence of internal courtyard and courtyard for wind flow. The model that exhibits the best width to length ratio and natural room environment is chosen for evaluation.The study was conducted in the residential areas of Dashilar Hutong, Jingyang, Deyang,Dongcheng District, Yue Hutong, Changchun Street Hutong Area, and Yongning District. The study is limited to the given areas only, and no evaluation is performed on other areas of the city and buildings that are not recently renovated or reconstructed. The study also provides recommendations to the architect firms and regulatory authorities regarding applications of green construction practices of the traditional courtyard houses on the renovation and reconstruction of contemporary residential buildings in Beijing. In the assessment, the spatial design of courtyards is balanced; the aspect ratio is planned to crate natural buffer space is created.</p> <p>Further, to examine the performance of the courtyard design the study applied the Computational Fluid Dynamics (C.F.D.) programming, Parabolic Hyperbolic, or Elliptic Numerical Integration Code Series (PHOENICS), for wind condition simulation. Later with the help of the Green build studio of Autodesk, the study had undergone Green Simulation. The Quadrangle courtyard building performance is analyzed by Green BuildingStudio to generate outputs like heating and cooling loads, and monthly electricity and fuel consumption, and their life cycle cost. Results show for a courtyard with a decent combination of courtyard layout and aspect ratiois chosen. Finally, the study suggests the best suited planning strategy for the new proposals and design implications for a new courtyard from the angle of green building construction.</p>