Computational Fluid Dynamics for urban physics: Importance, scales, possibilities, limitations and ten tips and tricks towards accurate and reliable simulations

Natural-gas fueled spark-ignition (SI) and compression-ignition (CI) engine performance and emissions

50 years of Computational Wind Engineering: Past, present and future

Wind energy is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal-Axis Wind Turbine (HAWT) or a Vertical-Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

Wind turbine design with emphasis on Darrieus concept Ion Paraschivoiu

In recent years, with the advent of globalization, the world is witnessing a steep rise in its energy consumption. The world is transforming itself into an industrial and knowledge society from an agricultural one which in turn makes the growth, energy intensive resulting in emissions. Energy modeling and energy planning is vital for the future economic prosperity and environmental security. Soft computing techniques such as fuzzy logic, neural networks, genetic algorithms are being adopted in energy modeling to precisely map the energy systems. In this paper, an attempt has been made to review the applications of fuzzy logic based models in renewable energy systems namely solar, wind, bio-energy, micro-grid and hybrid applications. It is found that fuzzy based models are extensively used in recent years for site assessment, for installing of photovoltaic/wind farms, power point tracking in solar photovoltaic/wind, optimization among conflicting criteria. The review indicates that fuzzy based models provide realistic estimates.

Applications of fuzzy logic in renewable energy systems – A review


 In recent times, drag-based vertical-axis wind turbine rotors have gained increasing interests in offshore applications because of their performance potential and reliability. Their advantages like simplicity, easier manufacture and lower maintenance cost have attracted the researcher’s attention toward improving their design further. However, this type of rotor is still suffering from lower efficiency than the lift-based Darrius and the horizontal-axis wind turbine rotors. A recently developed elliptical-bladed Savonius rotor has shown its potential to harvest wind energy more efficiently. However, the geometric parameters of this rotor such as aspect ratio, overlap ratio, number of blades, shaft and end plates, the aerodynamic parameters such as Reynolds number, lift and drag coefficients are needed to be optimized for further improvement of its performance. In the present investigation, the wind tunnel tests have been conducted to analyze the effect of shaft and end-plates of a newly developed elliptical-bladed vertical-axis Savonius wind turbine rotor. Experiments have been conducted over a range of tip speed ratios to find the torque and power coefficients of a two-bladed rotor system for two individual cases viz., the rotor with a shaft and the rotor with end-plates. In order to have a direct comparison, the experimental data are also obtained for the same rotor without the shaft and without the end-plates. The wind tunnel tests have demonstrated an improvement of power coefficient by 26.31% for the rotor with the end plates.

Analyzing the Effect of Shaft and End-Plates of a Newly Developed Elliptical-Bladed Savonius Rotor From Wind Tunnel Tests

Numerical Investigations on Flow Control over Blended-Wing-Body Transonic Aircraft Using Synthetic-Jet Actuators

The progress and prosperity of a nation like India depends largely upon the fossil fuel-based power production sectors. However, the use of these fuels leads to detrimental effects on the ecosystem because of various pollutants emitted from combustion of fossil fuel. Being the second largest populist country in the globe, India is heavily dependent on imported fossil fuels, thereby making it the major source of global warming and pollutant emission. The fossil energy in India is primarily used in transport and stationary power production sectors. Another problem with these fossil fuels is that it is located in the certain part of the globe which makes oil-deficient countries to depend on them. Therefore, an alternative arrangement is necessitated to reduce these dependencies and oil imports. Alternative renewable energy sources in the form of vegetable oil, biodiesel, biogas, producer gas, and alcohols have good prospects to replace or supplement fossil fuel. Oils derived from vegetables show the most promising fuel for diesel engines. However, vegetable oils have the lower calorific values along with the high viscosity and density as compared to diesel, which are not suitable properties to run the engine. Hence, these properties are improvised through blending, preheating, transesterifications, and emulsifications. Transesterification of vegetable oil yields biodiesel which is the most prominent and popular among the processes. Gaseous fuels such as biogas and producer gas have also been successfully implemented in diesel engine through the dual fuel mode. Stressing the importance of alternative fuel sources for diesel engines, the present study focuses on the effects of these arrangements on engine performance and emission characteristics.

Supplementing the Energy Need of Diesel Engines in Indian Transport and Power Sectors

A new approach is proposed here to control the two-level three-phase grid side converter. The proposed control strategy is an extended state observer (ESO)-based adaptive control, consists of two cascaded control loops. The adaptive-multi-input multi-output controller is employed in the inner control loop, which is used to regulate the active and reactive component of the grid currents. The outer-loop consists of an adaptive controller augmented with an ESO to regulate the DC bus voltage. The goal of the proposed control strategy is to maintain a unity power factor while keeping the DC bus voltage constant under a sudden change in load demand at DC side, i.e. change in the resistive load connected across the DC bus. The proposed adaptive controller in the inner control loop does not require any information about the parameters associated with the grid filter (L-filter), and hence, it is found to be more robust towards parametric variations. The ESO-based adaptive controller is compared with the classical proportional–integral control in real-time, and the comparison indicates that the proposed controller not only accomplishes a nearly flawless tracking performance but also delivers a complete robust performance against resistive load variation across the DC bus.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2019.1059

Development of an adaptive control strategy for the three‐phase grid side converter with wide range of parametric and load uncertainties

\n Over the last few decades, the vertical-axis wind turbines (VAWTs) have undergone intensive research mainly due to their design simplicity and independency of wind direction. The drag-based Savonius wind rotor exhibits a better starting capability, whereas the lift-based Darrieus wind rotor achieves higher efficiency over a wider operating range. Thus, in order to capitalize on their advantages, both the rotors are mounted on the same axis to form a hybrid/combined system. In this review paper, an attempt has been made to collect and analyze the past research studies in the field of hybrid wind rotors. An optimization route has also been suggested for the design of such a hybrid wind rotor to ensure that the design complexity is minimized, and at the same time, both the Savonius and the Darrieus rotors are utilized to their fullest potential. In this regard, a few important parameters are identified whose effects on the hybrid rotor performance must be investigated in future studies. Suggestions and direction of research are presented keeping in mind the improvement of the technology.

Ujjwal K. Saha

Papers

Analyzing the Effect of Shaft and End-Plates of a Newly Developed Elliptical-Bladed Savonius Rotor From Wind Tunnel Tests

Numerical Investigations on Flow Control over Blended-Wing-Body Transonic Aircraft Using Synthetic-Jet Actuators

Supplementing the Energy Need of Diesel Engines in Indian Transport and Power Sectors

Development of an adaptive control strategy for the three‐phase grid side converter with wide range of parametric and load uncertainties

Hybrid/Combined Darrieus–Savonius Wind Turbines: Erstwhile Development and Future Prognosis