the term hydrological drought is applied to represent low water levels in streams, reservoirs and lakes as well as a low groundwater level. base flow index (bfi) as one of low flow indices gives the ratio of base flow to total flow and investigates basin’s ability to store and release of water in drought periods. the objectives of this study were to determine bfi and to validate this index in d...

Modeling support for dynamic simulation of chemical-process flowsheets, which is of significant ®alue for plantwide dynamic simulation using differential ] algebraic model formulations, is to date ®ery limited when one or more unit models include partial differential equations. Se®eral new techniques that pro®ide modeling support for such simulations are presented. These techniques are based on...

Understanding and modeling of three-phase transient flow in gas-condensate wells play a vital role in designing and optimizing dynamic kill procedure of each well that needs to capture the discontinuities in density, geometry, and velocity of phases but also the effect of temperature on such parameters. In this study, two-phase Advection-Upstream-Splitting-Method (AUSMV) hybrid scheme is extend...

nowadays acoustic emission (ae) testing based on the kaiser effect (ke) is increasingly used to estimate the in-situ stress in laboratories. in this work, this effect is assessed on cylindrical specimens in numerical simulations of the cyclic loadings including loading, unloading, and re-loading cycles using a 3d code called the particle flow code (pfc) based upon the distinct element method. t...

water alternating gas (wag) technique is used in the petroleum industry to inject carbon dioxide (co2) into underground formations either for sequestration or enhanced oil recovery (eor) processes. co2 injection causes reactions with formation brine or aquifer and produces carbonic acid, the acid dissolves calcite and changes flow behavior significantly. modeling and investigating effects of co...

In this paper, in order to understand the flow-pipe interaction more clearly, the variations on flow pattern around semi-buried pipelines due to steady current have physically and numerically been investigated. In physical modeling section, the experiments have been carried out in a flume with 10 meter length, 0.3 meter width and 0.5 meter depth using a P.V.C pipe with 6.35 cm in diameter (for ...

In this paper, a mathematical model is developed to calculate the conversion and the residence time reaction for plug flow and mixed flow in the reactors filled with cylin-drical particles using the shrinking core model. In this modeling, the size of the particles is un-chamged during the reaction. Also, the reaction rate is controlled by the gas layer resistance, the ash layer resistance, and ...