Kalantari D.,University of Sari |
Tropea C.,TU Darmstadt
Fluid Dynamics and Materials Processing | Year: 2014
This study presents a combined experimental and theoretical investigation on the formation and spreading of a liquid film on a flat and rigid wall due to spray impact. A dual-mode phase Doppler instrument is used to characterise the spray while the average film thickness is measured using a high-speed CCD camera. The experimental results are complemented with theoretical expressions derived under the assumption that the spray is stationary. A new model for the prediction of the average wall film thickness is formulated taking into account the mean Reynolds number of the impacting drops, the flux density of the impacting droplets, and the average drop diameter. The theoretically determined average film thickness exhibits a good agreement with the measured data when the film can be considered thin. © 2014 Tech Science Press.
Safari Shad M.,University of Sari |
Habibnejad Roshan M.,University of Sari |
Ildoromi A.,University of Malayer
Journal of the Indian Society of Remote Sensing | Year: 2014
Because of the difficulty of monitoring and measuring snow cover in mountainous watersheds, satellite images are used as an alternative to mapping snow cover to replace the ground operations in the watershed. Snow cover is one of the most important data in simulation snowmelt runoff. The daily snow cover maps are received from Moderate Resolution Imaging Spectroradiometer (MODIS), and are used in deriving the snow depletion curve, which is one of the input parameters of the snowmelt runoff model (SRM). Simulating Snowmelt runoff is presented using SRM model as one of the major applications of satellite images processing and extracting snow cover in the Ghara - Chay watershed. The first results of modeling process show that MODIS snow covered area product can be used for simulation and forecast of snowmelt runoff in Ghara - Chay watershed. The studies found that the SCA results were more reliable in the study area. © 2013 Indian Society of Remote Sensing.
Arekhi S.,Golestan University |
Jafarzadeh A.A.,University of Sari
Arabian Journal of Geosciences | Year: 2014
Forest conversion due to illegal logging and agricultural expansion is a major problem that is hampering biodiversity conservation efforts in the Zagros region. Yet, areas vulnerable to forest conversion are unknown. This study aims to predict the spatial distribution of deforestation in western Iran. Landsat images dated 1988, 2001, and 2007 are classified in order to generate digital deforestation maps which locate deforestation and forest persistence areas. Meanwhile, in order to examine deforestation factors' investigation, deforestation maps with physiographic and human spatial variables are entered into the model. Areas vulnerable to forest changes in the Zagros forest region are predicted by a multilayer perceptron neural network (MLPNN) with a Markov chain model. The results show that about 19,294 ha forest areas are deforested in the last 19 years. The predictive performance of the model appears successful, which is validated using the actual land cover map of the same year from Landsat data. The validated map is found to be 94 % accurate. The validation is also tested using the relative operating characteristic approach which yielded a value of 0.96. The model is then further extended to predict forest cover losses for 2020. The MLPNN approach was found to have a great potential to predict land use/land cover changes because it permits developing complex, nonlinear models. © 2012 Saudi Society for Geosciences.
Kalantari D.,University of Sari
Fluid Dynamics and Materials Processing | Year: 2013
In this study, a critical summary of existing spray/wall interaction models is given in synergy with a review of available experimental data. In particular, special attention is devoted to the limitations, difficulties and complexities of the most used approaches in the literatures. An attempt is also made to indicate the bottlenecks and criticalities which typically arise when investigators try to extend results obtained for isolated droplets to the more complex dynamics produced by spray impacts. ©2013 Tech Science Press.