Water is essential for food security, industrial output, ecological sustainability, and a country’s socioeconomic progress. Water scarcity and environmental concerns have increased globally in recent years as a result of the ever-increasing population, rapid industrialization and urbanization, and poor water resource management. Even though there are sufficient water resources, their uneven circulation leads to shortages and the requirement for portable fresh water. More than two billion people live in water-stressed areas. Hence, the present study covers all of the research based on water extraction from atmospheric air, including theoretical and practical (different experimental methods) research. A comparison between different results is made. The calculated efficiency of the systems used to extract water from atmospheric air by simulating the governing equations is discussed. The effects of different limitations, which affect and enhance the collectors’ efficiency, are studied. This research article will be very useful to society and will support further research on the extraction of water in arid zones.

At present, surveillance is attracting attention in the field of UAV development. In particular, border surveillance plays a vital role in obtaining the required data around the border and for assisting in military operations. The primary function of this Hybrid UAV (VTOL and Fixed Wing) is to provide prerequisite data, captured during day/night surveillance, to the respective database. One of the primary problems that arise in border patrolling is the use of the UAV under different environmental conditions, thereby reducing its endurance firmly. In addition to the surveillance equipment, energy harvesting techniques are involved in solving the problem of endurance. The piezoelectric energy harvester and solar panels are added to harvest electrical energy in the UAV. Based on this application, the conceptual design of the Hybrid UAV, based on nature, was designed and investigated theoretically, as well as computationally. A series of analysis, which includes Computational Fluid Dynamics, Finite Element Analysis and Analytical approach, was used to determine the energy harvested from the energy harvester. This work confirms the proposed integrated engineering approach for the estimation of renewable energy, via PVEH patches, and the same approach is thus offered to researchers for subsequent applications. Additionally, a hybrid energy idea for newly developed drones was proposed in this work. This concept will be extensively used in the unmanned aircraft system sectors.

The impacts of conflicting aerodynamic forces and side drifting forces are the primary unstable elements in automobiles. The action of an unstable environment in automobile vehicles increases the chance of an accident occurring. As a result, much study is required to determine how opposing aerodynamic forces and side drifting force affects function, as well as how to deal with them for safe and smooth navigation. In this work, an intercity bus is chosen as a main object, and computational fluid dynamics (CFD) analysis is used to estimate aerodynamic forces on the bus in all major directions. Experimentation is also carried out for validation reasons. CFD findings for a scaled base model and a dimple-loaded model based on experimental results from a subsonic wind tunnel are demonstrated to be correct. The drag forces generated by CFD simulations on test models are carefully compared to the experimental drag findings of same-dimensioned models. The error percentages between the results of these two methods are acquired and the percentages are determined to be within an acceptable range of significant limitations. Following these validations, CATIA is used to create a total of nine distinct models, the first of which is a standard intercity bus, whereas the other eight models are fitted with drag reduction techniques such as dimples, riblets, and fins on the surface of their upper cumulus side. A sophisticated computational tool, ANSYS Fluent 17.2, is used to estimate the comparative assessments of the predictions of aerodynamic force fluctuations on bus models. Finally, dimples on the top and side surfaces of the bus model (DESIGN–I) are proposed as a more efficient model than other models because dimples are a vital component that may lower pressure drag on the bus by 18% in the main flow direction and up to 43% in the sideslip direction. Furthermore, by minimizing the different aerodynamic force sources without impacting the preparatory needs, the proposed model may provide comfortable travel. The real-time bus is created, and the finalized drag reduction is applied to the optimized places over the whole bus model. In addition, five distinct size-based bus models are developed and studied in terms of aerodynamic forces, necessary energy to resist aerodynamic drag, required forward force for successful movement, instantaneous demand for particular power, and fuel consumption rate. Finally, the formation of aeroacoustic noise owing to turbulence is estimated using sophisticated computer simulation. Last, for real-time applications, multi-parametric studies based on appropriate intercity buses are established.