Showing papers in "Engineering Applications of Computational Fluid Mechanics in 2019"
TL;DR: In this paper, ensemble models using the Bates-Granger approach and least square method are developed to combine forecasts of multi-wavelet artificial neural network (ANN) models for predicting chlorophyll a and salinity with different lead.
Abstract: In this study, ensemble models using the Bates–Granger approach and least square method are developed to combine forecasts of multi-wavelet artificial neural network (ANN) models. Originally, this study is aimed to investigate the proposed models for forecasting of chlorophyll a concentration. However, the modeling procedure was repeated for water salinity forecasting to evaluate the generality of the approach. The ensemble models are employed for forecasting purposes in Hilo Bay, Hawaii. Moreover, the efficacy of the forecasting models for up to three days in advance is investigated. To predict chlorophyll a and salinity with different lead, the previous daily time series up to three lags are decomposed via different wavelet functions to be applied as input parameters of the models. Further, outputs of the different wavelet-ANN models are combined using the least square boosting ensemble and Bates–Granger techniques to achieve more accurate and more reliable forecasts. To examine the efficiency and reliability of the proposed models for different lead times, uncertainty analysis is conducted for the best single wavelet-ANN and ensemble models as well. The results indicate that accurate forecasts of water temperature and salinity up to three days ahead can be achieved using the ensemble models. Increasing the time horizon, the reliability and accuracy of the models decrease. Ensemble models are found to be superior to the best single models for both forecasting variables and for all the three lead times. The results of this study are promising with respect to multi-step forecasting of water quality parameters such as chlorophyll a and salinity, important indicators of ecosystem status in coastal and ocean regions.
191 citations
TL;DR: In this article, thermal conductivity of thermmosyphons has been investigated for different heat transfer purposes including cooling devices and heat exchangers, and thermal performance of thermal performan...
Abstract: Thermosyphons have high effective thermal conductivity and are applicable for different heat transfer purposes including cooling devices and heat exchangers. In the present study, thermal performan...
152 citations
TL;DR: In this article, the current theoretical models for nanofluid viscosity prediction are only applicable across a wide range of convective heat transfer phenomena, such as convective convective heating and cooling.
Abstract: Nanofluid viscosity is an important physical property in convective heat transfer phenomena. However, the current theoretical models for nanofluid viscosity prediction are only applicable across a ...
106 citations
TL;DR: An adaptive-network-based fuzzy inference system (ANFIS) is used to train four big data inputs with a novel integration of computational fluid dynamics (CFD) model of gas to show that the increasing number of input variables improves the intelligence of the ANFIS method.
Abstract: The combination of machine learning and numerical methods has recently become popular in the prediction of macroscopic and microscopic hydrodynamics parameters of bubble column reactors. Such numerical combination can develop a smart multiphase bubble column reactor with the ability of low-cost computational time when considering the big data. However, the accuracy of such models should be improved by optimizing the data parameters. This paper uses an adaptive-network-based fuzzy inference system (ANFIS) to train four big data inputs with a novel integration of computational fluid dynamics (CFD) model of gas. The results show that the increasing number of input variables improves the intelligence of the ANFIS method up to R=0.99, and the number of rules during the learning process has a significant effect on the accuracy of this type of modeling. Furthermore, the proper selection of model’s parameters results in higher accuracy in the prediction of the flow characteristics in the column structure.
104 citations
TL;DR: In this article, the authors have shown that silver nano particles have antimicrobial property which makes them appropriate for disinfection. Due to their antimicrobial feature, these particles are applicable for root canal irrigation.
Abstract: Silver nano particles have antimicrobial property which makes them appropriate for disinfection. Due to their antimicrobial feature, these particles are applicable for root canal irrigation...
101 citations
TL;DR: In this paper, the efficiency of evaporation rate is analyzed in the context of water management. But, the efficiency is not evaluated in terms of the number of people who use the water.
Abstract: Evaporation rate is one of the key parameters in determining the ecological conditions and it has an irrefutable role in the proper management of water resources. In this paper, the efficiency of s...
100 citations
TL;DR: A novel prediction model for RSL of road pavement using support vector regression (SVR) optimized by particle filter to overcome the challenges is presented and the results show the superiority of the proposed model with a correlation coefficient index equal to 95%.
Abstract: Accurate prediction of the remaining service life (RSL) of pavement is essential for the design and construction of roads, mobility planning, transportation modeling as well as road management syst...
92 citations
TL;DR: The new developed AMR-IBM algorithm is validated using a benchmark data of fluid past a cylinder and the results show that there is good agreement under laminar flow, confirming the robustness of the new algorithms in simulating flow characteristics in the boundary layers of thin structures.
Abstract: This study aims to develop an adaptive mesh refinement (AMR) algorithm combined with Cut-Cell IBM using two-stage pressure–velocity corrections for thin-object FSI problems. To achieve the objectiv ...
90 citations
TL;DR: In this article, the flutter behavior of a typical wing is investigated by presented Deferential Quadrature Method (DQM) and the aerodynamic part adopted Wagner functions to model it.
Abstract: In this paper the flutter behavior of a typical wing is investigated. The study is performed by presented Deferential Quadrature Method (DQM). The aerodynamic part adopted Wagner functions to model...
85 citations
TL;DR: In this article, the optimization of the first blade of a new test rig is pursued using a hybrid model comprising the genetic algorithm, artificial neural networks and design of experiments, and the results show that the hybrid model outperforms the conventional methods.
Abstract: In this paper, optimization of the first blade of a new test rig is pursued using a hybrid model comprising the genetic algorithm, artificial neural networks and design of experiments. Blade tuning...
83 citations
TL;DR: In this paper, the boundary element method-finite element method (BEM-FEM) model is employed to investigate the sloshing and flexibility terms of elastic submerged structures on the behavior of a c...
Abstract: In this study, the boundary element method–finite element method (BEM-FEM) model is employed to investigate the sloshing and flexibility terms of elastic submerged structures on the behavior of a c...
TL;DR: A comprehensive review is conducted to recognize the feasibility of EC models and their potential in simulating ETo in a wide range of environments and several possible future research directions are proposed for the investigations of ETo using EC.
Abstract: Evapotranspiration is one of the most important components of the hydrological cycle as it accounts for more than two-thirds of the global precipitation losses. Indeed, the accurate prediction of r...
TL;DR: The most vital meteorological variables which affect plant growth are solar radiation, moisture and temperature as discussed by the authors, due to the fact that the global solar radiation (GSR) is scarcely gauged at meteorologists.
Abstract: Solar radiation, moisture and temperature are the most vital meteorological variables which affect plant growth. Due to the fact that the global solar radiation (GSR) is scarcely gauged at meteorol...
TL;DR: In this paper, the authors describe the effect of dynamic viscosity on the heat transfer and flow of fluids with nanostructures, and the authors propose a method to improve the thermophysical properties of these types of fluids.
Abstract: Dynamic viscosity considerably affects the heat transfer and flow of fluids. Due to improved thermophysical properties of fluids containing nanostructures, these types of fluids are widely employed...
TL;DR: In this paper, a group method of data handling (GMDH) neural network was used to predict thermal resistance and effective thermal conductivity of pulsating heat pipes (PHPs) filled with water as working fluid.
Abstract: Thermal performance of pulsating heat pipes (PHPs) is dependent to several factors. Inner and outer diameter of tube, filling ratio, thermal conductivity, heat input, inclination angle, and length of each section are the most influential factors in the design process of PHPs. Since water is a conventional working fluid for PHPs, thermal resistance and effective thermal conductivity of PHPs filled with water are modeled by applying a GMDH (group method of data handling) neural network. The input data of the GMDH model are collected from other experimental investigations to predict the physical properties including thermal resistance and effective thermal conductivity of PHPs filled with water as working fluid. The accuracy of the introduced models are examined through the R2 tests and resulted in 0.9779 and 0.9906 for thermal resistance and effective thermal conductivity, respectively.
TL;DR: An extensive variety of chemical engineering processes include the transfer of heat energy as discussed by the authors, and increasing the effective contact surface is known as one of the popular manners to improve the effi ciency.
Abstract: An extensive variety of chemical engineering processes include the transfer of heat energy. Since increasing the effective contact surface is known as one of the popular manners to improve the effi...
TL;DR: The results indicate that the application of MLP and ANFIS results in the accurate prediction of scour geometry for the designing of stable grade control structures in alluvial irrigation channels.
Abstract: The main aims and contributions of the present paper are to use new soft computing methods for the simulation of scour geometry (depth/height and locations) in a comparative framework. Five models ...
TL;DR: In this article, the numerical simulation of air pollution by particles with different sizes from the Ekibastuz State district power plant-1 (Ekibastaus SDPP-1), which is located on the...
Abstract: In this paper, was presented the numerical simulation of air pollution by particles with different sizes from the Ekibastuz State district power plant-1 (Ekibastuz SDPP-1), which is located on the ...
TL;DR: In this paper, the authors proposed a new model for predicting evaporation losses from reservoirs, which is an essential component of reservoir management and operation, and demonstrated that the model has a better prediction performance than conventional models.
Abstract: Reliable prediction of evaporative losses from reservoirs is an essential component of reservoir management and operation. Conventional models generally used for evaporation prediction have a numbe...
TL;DR: In this article, the accurate prediction of SiO2 nanofluid effect on the SiO 2 was investigated, and the results showed that the prediction was accurate in terms of the number of atoms and the amount of energy consumed.
Abstract: Nanofluids have found extended applications in different industrial and engineering systems nowadays. This study aims to investigate the accurate prediction of SiO2 nanofluid effect on the ...
TL;DR: To support initiatives for global emissions targets set by the United Nations Framework Convention on climate change, sustainable extraction of usable power from freely-available global solar radia is proposed in this paper, where the authors propose a method to support the global emissions reduction.
Abstract: To support initiatives for global emissions targets set by the United Nations Framework Convention on climate change, sustainable extraction of usable power from freely-available global solar radia...
TL;DR: In this article, numerical results of the thermal pollution from the operation of a power plant are presented when using the Irtysh River as a natural water cooling system, and a two-dim...
Abstract: In this paper, obtained numerical results of the thermal pollution from the operation of a power plant are presented when using the Irtysh River as a natural water cooling system. A two-dim...
TL;DR: Artificial neural network (ANN) is widely used in engineering applications in order to provide predicting models to estimate the performance of the studied system under specific working conditions as mentioned in this paper, and it is used in many engineering applications.
Abstract: Artificial neural network (ANN) is widely being used in engineering applications in order to provide predicting models to estimate the performance of the studied system under specific working condi...
TL;DR: Two promising soft-computing algorithms were employed to develop reliable and simple to use paradigms to predict the temperature dependency of Krw and Kro in TEOR, and GEP correlations were found to be the most consistent with root mean square error values.
Abstract: In the implementation of thermal enhanced oil recovery (TEOR) techniques, the temperature impact on relative permeability in oil–water systems (Krw and Kro) is of special concern. Hence, de...
TL;DR: In this article, the authors employ turbine flow meters to measure natural gas which delivered to Compressed Natural Gas stations, and use compressors to increase pressure to increase the efficiency of the turbines.
Abstract: Natural companies employ turbine flow meters to measure natural gas which delivered to Compressed Natural Gas stations. The stations utilize compressors to increase pressure. The compressor produce...
TL;DR: In this article, the rotational speed of EHA pumps is increased to improve their power density, but gaseous cavitation tends to occur in the displacement chambers at high velocities.
Abstract: Raising the rotational speed of electro-hydrostatic actuator (EHA) pumps is a useful way to improve their power density. However, gaseous cavitation tends to occur in the displacement chambers at h...
TL;DR: The regime of compressible flow generally refers to the super/subsonic case, however, several remarkable cases with low Mach number could not be appropriately described with the incompressible flow regime.
Abstract: The regime of compressible flow generally refers to the super/subsonic case. However, several remarkable cases with low Mach number could not be appropriately described with the incompressi...
TL;DR: The methodology proposed to determine the behavior car dynamics with unsteady aerodynamic effects taken into account appears to be a significant improvement when compared with existing methodologies used for such an assessment.
Abstract: This study investigates the impact of unsteady aerodynamic loads on the behavior of car dynamics during braking maneuvers. In the analysis, two independent solvers were coupled to solve an existing...
TL;DR: In this article, a mathematical formulation of two-phase flows at an aerator remains a challenging issue for spillway design due to their complexities in terms of water-air interactions subjected to high flow velocities.
Abstract: Mathematical formulations of two-phase flows at an aerator remain a challenging issue for spillway design. Due to their complexities in terms of water-air interactions subjected to high flow veloci ...
TL;DR: In this paper, the main innovation is the use of a novel energo-environmental approach for investigation of biogas production, and analysis of the amount of methane and Biogas produced in terms of en...
Abstract: The main innovation of the study is the use of a novel energo-environmental approach for investigation of biogas production, and analysis of the amount of methane and biogas produced in terms of en...