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Flow in river bends is associated with generation of secondary flows, which leads to the development of a rather complicated flow pattern around bridge piers located in the bend. The present study investigated the flow patterns around models for rectangular and oblong piers with a collar located at the 90-degree angle of a 180-degree sharp bend in an experimental plume. The 3D flow velocity data were collected using a Vectrino velocimeter. The experimental results indicated that the presence of the rectangular pier caused a more intense deviation of the streamlines towards the outer bank of the bend. Furthermore, installation of the oblong pier, rather than the rectangular pier, decreased the maximum secondary flow power and angular velocity by 35% and 45%, respectively. It was also found that the maximum turbulence kinetic energy around the two piers was not significantly different; however, by installing the rectangular pier, a region with high values of turbulence kinetic energy was formed at 90 near the inner bank. Moreover, installation of the oblong pier could reduce shear stress. [ABSTRACT FROM AUTHOR]

Spouted beds are extensively used in different industries. The minimum spouting velocity is a critical hydrodynamic parameter needed for the design and scale-up of these systems. This study deals with an ensemble method involving Multi-Layer Perceptron (MLP) network, the Adaptive Neuro-fuzzy Inference System (ANFIS), the Gaussian Process Regression (GPR), and a Regression Tree (RT) model for predicting minimum spouting velocity for coarse particles in conical spouted beds equipped with nonporous draft tubes (CSBDTs) and conical-cylindrical spouted beds. Some dimensionless variables related to the physical properties of the conical bed and particles' material were constructed and used as model inputs. The proposed method was validated against the measured data. The results revealed that the ensemble method was capable of predicting the minimum spouting velocity with an average absolute relative error (AARE) of 10.52% and 10.35% for the testing data points in the case of CSBDTs and conventional spouted beds, respectively. It was also shown that the proposed ensemble method provided the best results in comparison with the other methods. Therefore, the ensemble method is a useful and powerful technique for predicting the minimum spouting velocity in spouted beds with and without the draft tube. [ABSTRACT FROM AUTHOR]

In recent years, the construction of high-rise buildings as an urban development strategy has been accepted in many megacities. High-rise buildings have positive as well as negative impacts on urban environments. Therefore, the environmental impact assessment of high-rise buildings for establishing strategies to ensure sustainable and resilient urban development is essential. In this study, the environmental impact of high-rise buildings with a resilient development mindset was assessed. Resilience mindset provides an approach for including the uncertainties and interdependence of systems and processes for planning new sustainable developments and assessment methods. The corresponding environmental impact assessment was performed by monitoring the structural changes and their impacts on the function of ecosystem and environmental services. Here, the positive and negative impacts of high-rise buildings were evaluated. Protection of impervious surfaces as a positive impact and changing the natural pattern of urban wind flow as a negative impact were considered. The transparency of the results and the reduction of uncertainty are the advantages of using the resilience mindset in the environmental impact assessment. The results of this study suggest that the resilient development mindset can improve the environmental assessment through the adoption of appropriate indicators on multiple scales and differentiating between the primary and secondary effects. [ABSTRACT FROM AUTHOR]

Byline: M. Chrigui, A. Sadiki, G. Ahmadi The objective of this work is to analyse the interaction between evaporating droplets and the turbulent flow of the carrier gas using a second order turbulence RANS modelling in an Euler-Lagrangian approach including two-way coupling. The analysis is performed in a vertical isopropanol polydispersed spray issuing into a co-flowing, heated air stream. The results mainly display the turbulence modulation effects besides the turbulent dispersion of evaporating droplets: 1) The influence of droplet diameter and interface transport on the gas phase turbulence as well as 2) The effect of the droplet evaporation on the mass and heat transfer processes are compared with experimental data. 3) The reciprocal influence of the modification of interface transport by turbulence, i.e., the influence of the turbulent fluctuations of different quantities (such as velocity, temperature, etc.) on the droplet evaporation (through the mass and heat evaporation rates, the droplets diameter distribution) are computed and discussed.

A set of computational models, denoted extended group function models, are introduced for describing intermolecular interactions of closed shell systems. The models have the following properties: They have a conceptual structure which facilitates interpretation. The models can be applied for any intersystem distances. The models are size extensive. The basis set superposition error can be eliminated at the correlation level. The models are computationally efficient. A test calculation is performed on the complex Ne·Li+. [ABSTRACT FROM AUTHOR]

A new computational method within the framework of extended group function models is introduced for describing intermolecular interactions between closed shell systems. The model is size extensive, applicable for any intersystem distance, and has a conceptual structure which facilitates interpretation. The basis set superposition error can be eliminated at the correlation level. Test calculations have been performed on the helium dimer and the helium trimer. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]