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hydrodynamics
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A fully explicit incompressible Smoothed Particle Hydrodynamics method for multiphase flow problems
, Article Engineering Analysis with Boundary Elements ; Volume 143 , 2022 , Pages 501-524 ; 09557997 (ISSN) ; Hopp Hirschler, M ; Shadloo, M. S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Multiphase flow is a challenging area of computational fluid dynamics (CFD) due to their potential large topological change and close coupling between the interface and fluid flow solvers. As such, Lagrangian meshless methods are very well suited for solving such problems. In this paper, we present a new fully explicit incompressible Smoothed Particle Hydrodynamics approach (EISPH) for solving multiphase flow problems. Assuming that the change in pressure between consecutive time-steps is small, due to small time steps in explicit solvers, an approximation of the pressure for following time-steps is derived. To verify the proposed method, several test cases including both single-phase and...
New insight into hydrodynamic and cake erosion mechanism during rotating-disk dynamic microfiltration of concentrated bentonite suspensions at different salinity conditions
, Article Separation and Purification Technology ; Volume 300 , 2022 ; 13835866 (ISSN) ; Jamshidi, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The present study investigates the dynamic filtration of concentrated slurry fluids containing colloidal clay particles under different salinity, shear flow, and flux rate conditions. The dynamic filtration study was carried out by the filtration cell equipped with a rotating disk to apply shear stress over the membrane surface. A 3D CFD simulation has been implemented to model the hydrodynamic flows inside the filtration cell to obtain the wall shear stress (WSS) on the membrane surface at different disk rotation speeds. The thickness and surface patterns of fouling were captured utilizing a surface profilometer. First, the cake-filtration model was used to predict the flux rate and fouling...
Experimental and numerical investigation of hydrodynamic performance of a new surface piercing propeller family
, Article Ocean Engineering ; Volume 264 , 2022 ; 00298018 (ISSN) ; Teimouri, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Today, passenger and racing boats increasingly utilize surface-piercing propellers. This type of propeller operates in two distinct phases of water and air simultaneously. As a result, this propeller type has additional characteristics that must be investigated separately from conventional propellers. A new family of surface piercing propellers was investigated using experimental and numerical methods. The family consisted of five propeller models with varying geometric features operating at an immersion ratio of 0.7. Experiments were conducted in the Sharif University of Technology's hydrodynamic group's cavitation tunnel. Additionally, using Star-CCM + software, the numerical simulation...
Nanofluid preparation, stability and performance for CO2 absorption and desorption enhancement: A review
, Article Journal of Environmental Management ; Volume 313 , 2022 ; 03014797 (ISSN) ; Rahimi, K ; Saghandali, F ; Scott, J ; Lovell, E ; Sharif University of Technology
Academic Press
2022
Abstract
In recent years, the importance of capturing CO2 has increased due to the necessity of minimizing climate change and the detrimental effects of CO2 emissions from industrial processes. CO2 absorption, as one of the most mature carbon capture technologies, has been improved by introducing nanosized particles into liquid absorbents. Nanofluids have been the subject of interest in many studies recently due to their tremendous impact on absorption. This review comprehensively examines the CO2 absorption behavior for nanofluids through the investigation of different absorption systems. Potential mechanisms for improving the absorption/regeneration performance of nanoabsorbents as well as the...
Numerical simulations of the hydrodynamic performance of the propeller with wake equalizing duct behind the ship
, Article Scientia Iranica ; Volume 29, Issue 5 B , 2022 , Pages 2332-2348 ; 10263098 (ISSN) ; Bamdadinejad, M ; Ghassemi, H ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
The equalizing wake flow into the propeller behind the ship is important from the hydrodynamic performance viewpoint. In this study, numerical simulations of the DTMB4119 propeller with two symmetric and asymmetric duct types behind the KRISO Container Ship (KCS) are performed using Computational Fluid Dynamics (CFD). In order to improve the wake equaling flow, a combined duct and stators' configurations are installed before the propeller in the stern of the ship and its hydrodynamic performance is studied using CFD. A duct with the NACA4415 section and two types of stator configurations are selected. The STAR-CCM+ software using the finite volume discretization method was used to solve the...
Integrated numerical study of rainfall-induced landslides from initiation to propagation using saturation-based rheological model
, Article Scientia Iranica ; Volume 29, Issue 5 B , 2022 , Pages 2304-2316 ; 10263098 (ISSN) ; Manzari, M. T ; Hajilouy Benisi, A ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
This paper presents an integrated two-dimensional numerical framework for simulating rainfall-induced landslides from instability initiation to post-failure flow. To describe the entire process, three steps are considered in this study: (1) a coupled hydrostability analysis which detects the failure plane using the Finite Element Method (FEM) (pre-failure stage); (2) computing the local rheology of the failed mass (wet sandy soil) based on the water saturation at the onset of failure using the saturation-based rheological model (transition stage); and (3) a continuum-based propagation analysis which solves the flow of the wet material employing the Smoothed Particle Hydrodynamics (SPH)...
Observational comparative study in Kühni and ORC agitated columns for the mechanism and performance of molybdenum extraction under various hydrodynamic conditions
, Article International Journal of Heat and Mass Transfer ; Volume 185 , 2022 ; 00179310 (ISSN) ; Torkaman, R ; Torab-Mostaedi, M ; Asadollahzadeh, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The present work is expressed to interpret the hydrodynamic parameters of rotation extraction columns in the reactive and non-reactive systems. The solvent extraction technique has been utilized for optimizing the transportation of molybdenum ions to the organic phase in two agitated columns (ORC and Kühni columns). Dispersed phase volume fraction, average droplet diameter, slip velocity, size distribution, and ions permeability of the aqueous phase have been investigated in terms of changing the operational variables including the agitation rate, flow rate of the inlet dispersed and continuous phases, column geometry, and reaction conditions. By considering the reactive and non-reactive...
Equatorial magnetoplasma waves
, Article Physical Review B ; Volume 105, Issue 20 , 2022 ; 24699950 (ISSN) ; Kargarian, M ; Efimkin, D. K ; Sharif University of Technology
American Physical Society
2022
Abstract
Due to its rotation, Earth traps a few equatorial ocean and atmospheric waves, including Kelvin, Yanai, Rossby, and Poincaré modes. It has been recently demonstrated that the mathematical origin of equatorial waves is intricately related to the nontrivial topology of hydrodynamic equations describing oceans or the atmosphere. In the present work, we consider plasma oscillations supported by a two-dimensional electron gas confined at the surface of a sphere or a cylinder. We argue that in the presence of a uniform magnetic field, these systems host a set of equatorial magnetoplasma waves that are counterparts to the equatorial waves trapped by Earth. For a spherical geometry, the equatorial...
A comprehensive theoretical approach for analysing manoeuvring effects on ships by integrating hydrodynamics and power system
, Article IET Electrical Systems in Transportation ; Volume 12, Issue 2 , 2022 , Pages 89-101 ; 20429738 (ISSN) ; Peyghami, S ; Parniani, M ; Blaabjerg, F ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Ship motions affect the propulsion system, which causes fluctuations in the power system. Mutually, the power system variations impact the ship velocity by generating speed changes in the propeller. Therefore, interconnecting the ship hydrodynamic and power system has paramount importance in designing and analysing an all-electric ship (AES). The lack of an integrated model that can be evaluated in various operating conditions, such as manoeuvring, is evident. This paper explores the required perceptions for the power system and hydrodynamic analysis of an AES. Then, an integrated theoretical model comprising both the ship motion and power system is proposed. In addition to providing an...
Stability analysis of parametric resonance in spar-buoy based on Floquet theory
, Article Ocean Engineering ; Volume 266 , 2022 ; 00298018 (ISSN) ; Abazari, A ; Behzad, M ; Hayatdavoodi, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Parametric resonance is a phenomenon caused by time-varying changes in the parameters of a system which may result in undesirable motion responses and instability. Floating bodies like ships and spar-buoys are prone to Mathieu instability mainly due to the instantaneous change of the metacentric height. With the fast-growing developments in Ocean Renewable Energy systems, spar-buoys are commonly used for wave energy convertors and floating wind turbines. Undesirable, unstable motions as a result of the parametric resonance can be problematic as it may cause inefficiency in operations and structural risk integrity. In this research, a new approach has been developed to investigate these...
Experimental and numerical investigation of squat submarines hydrodynamic performances
, Article Ocean Engineering ; Volume 266 , 2022 ; 00298018 (ISSN) ; Abbaspour, M ; Dolatshahi, K. M ; Sarraf, S ; Sani, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper empirically examines the hydrodynamic performances of squat submarines under the resistance and wave tests beside numerical investigation of pressure drag reduction techniques. Despite vast information about the operation of the streamlined fluid vessels, there is not much information about the geometries and hydrodynamic behaviors of squat vessels with L/D ratios below four. This study experimentally investigates the impacts of various relative depths and flow inclinations, intending to find drag, heave, and sway forces at the velocities of 0.5, 1.0, 1.5, 2.0, and 2.5-m/s. A one-tenth scaled model of a squat submarine is examined under the resistance and wave train scenarios as...
Numerical study and acoustic analysis of propeller and hull surface vessel in self-propulsion mode
, Article Ships and Offshore Structures ; Volume 17, Issue 11 , 2022 , Pages 2488-2497 ; 17445302 (ISSN) ; Norouzi Keshtan, M ; Jafarian, M. M ; Bagheri, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In this article, the hydrodynamic analysis and noise of the propeller and the surface vessel hull were examined. The model selected in this study is a KRISO Container Ship (KCS) with a five-bladed propeller. Initially, the hydrodynamic analysis of the propeller in open water mode and then in self-propulsion mode was investigated using computational fluid dynamics. Simulations were carried out using a commercial solver, STAR-CCM+ (RANS equations with FVM and VOF model). Finally, the emitted noise from the propeller and the vessel hull was investigated using Fox William Hawkins equations. The pressure distribution and hydrodynamic performance (thrust, torque, efficiency) of the propeller in...
Computer simulation of the effect of particle stiffness coefficient on the particle-fluid flows
, Article Particulate Science and Technology ; Volume 40, Issue 2 , 2022 , Pages 233-242 ; 02726351 (ISSN) ; Rajabi, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
The Computational fluid dynamics (CFD)–discrete element method (DEM) numerical simulation may be applied to predict the hydrodynamic behavior of dense particle–fluid flows. The main drawback of this simulation is the long computational time required owing to the large number of particles and the minute time-step required to maintain a stable solution. In this work, a new method to improve the efficiency and accuracy of CFD–DEM simulations is presented. The particle stiffness coefficient is used as a flexible parameter to improve the accuracy and efficiency of the model. The particle concentration distribution results are compared with experimental one’s to derive the optimum effective...
Exact hydrodynamic description of pilot plant Oldshue-Rushton contactor: a case study with the introduction of selenium and tellurium into reaction system
, Article International Journal of Environmental Analytical Chemistry ; Volume 102, Issue 16 , 2022 , Pages 4191-4207 ; 03067319 (ISSN) ; Torkaman, R ; Torab Mostaedi, M ; Asadollahzadeh, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In this paper, the hydrodynamic behaviour of the chemical reaction system (selenium, tellurium, and TBP) was interpreted in the Oldshue-Rushton extraction column. The optimum operating parameters for extracting the selenium and tellurium from chloride medium were carried out by using the batch experiments. The feed acidity of 5 molar and solvent phase with 20% (v/v) TBP in kerosene were optimised to examine the hydrodynamic parameters of the mentioned column. The impacts of operating variables such as rotor speed, inlet aqueous phase velocity, and inlet solvent phase velocity on the dispersed phase hold-up, mean drop size, slip velocity, drop size distribution, and extraction rate were...
An experimental investigation of hydrodynamic performance, cavitation, and noise of a normal skew B-series marine propeller in the cavitation tunnel
, Article Ocean Engineering ; Volume 238 , 2021 ; 00298018 (ISSN) ; Razaghian, A. H ; Tootian, A ; Seif, M. S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In this paper, the hydrodynamic performance, cavitation inception, and acoustic performance of a 5-bladed B-series propeller are experimentally investigated in the Sharif University of Technology cavitation tunnel. For hydrodynamic performance, thrust, torque, and efficiency of the propeller model were measured in open water tests. In the cavitation study, in addition to blade cavitation, tip vortex cavitation was also observed, and the cavitation bucket diagram was extracted in different advance coefficients. Finally, for the acoustic analysis of the propeller, the emitted noise in the cavitation tunnel was recorded using two hydrophones according to the recommended procedures of the...
Influence of surface-modified nanoparticles on the hydrodynamics of rising bubbles
, Article Chemical Engineering and Technology ; Volume 44, Issue 3 , 2021 , Pages 513-520 ; 09307516 (ISSN) ; Bastani, D ; Lotfi, M ; Miller, R ; Sharif University of Technology
Wiley-VCH Verlag
2021
Abstract
Local velocities of bubbles rising in four different nanosilica solutions were investigated experimentally. Also, the density, viscosity, and surface tension of fumed nanosilica and modified nanosilica solutions were measured. Heat treatment and chemical functionalization were used to modify the properties of silica nanoparticles. It was found that the addition of nanosilica affected the hydrodynamics of the rising bubble by increasing the drag friction at the interface. However, environmentally responsive nanosilica particles behaved like surfactant molecules, due to the interfacial activity of hydrophilic and hydrophobic chains. Silica nanoparticles coated with both hydrophilic and...
Investigation of the effect of the added mass fluctuation and lateral vibration absorbers on the vertical nonlinear vibrations of the offshore wind turbine
, Article Nonlinear Dynamics ; Volume 103, Issue 2 , 2021 , Pages 1499-1515 ; 0924090X (ISSN) ; Moradi, H ; Vossoughi, G ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
In this article, the effects of the changes in the mass of the floating wind turbine (as a multi-body system) on its nonlinear vertical vibrations are investigated. The fluctuations of the hydrodynamic added mass of the floating platform and the mass of the vibration absorbers, which added to the structure to mitigate the lateral vibrations, change the mass and consequently the dynamics of the vertical vibrations. In this regard, first, the governing equations of the vertical vibrations of the floating wind turbine are derived. The FAST code is used to validate the proposed model of the dynamics of the vertical vibrations through numerical simulations. Then, derived equations are solved...
Comprehensive hydrothermal analysis of an inclined mini-channel with fin array: by dual/multi-relaxation-time LBM and experimental process on SiO2-glycol rheological/thermal characteristics
, Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 31, Issue 7 , 2021 , Pages 2405-2429 ; 09615539 (ISSN) ; Hejri, S ; Akbar, N ; Hasani Malekshah, E ; Sharif University of Technology
Emerald Group Holdings Ltd
2021
Abstract
Purpose: The purpose of this study is to present a comprehensive hydrothermal analysis on an inclined mini-channel using numerical and experimental techniques. The fin array acts as heat source within the channel, and a wavy wall located at the top of the channel is heat sink. The side walls are insulated with curved profiles. Also, the channel is inclined with four known inclination angles. To solve the governing equations, the dual-multi-relaxation-time lattice Boltzmann method with D2Q9 and D2Q5 lattice models for flow and temperature fields is used, respectively. Also, the channel is filled with SiO2-glycol nanofluid. Design/methodology/approach: Identifying the behavior of a thermal...
High-throughput, label-free isolation of white blood cells from whole blood using parallel spiral microchannels with u-shaped cross-section
, Article Biosensors ; Volume 11, Issue 11 , 2021 ; 20796374 (ISSN) ; Rostami, P ; Saidi, M. S ; Firoozabadi, B ; Kashaninejad, N ; Sharif University of Technology
MDPI
2021
Abstract
Rapid isolation of white blood cells (WBCs) from whole blood is an essential part of any WBC examination platform. However, most conventional cell separation techniques are labor-intensive and low throughput, require large volumes of samples, need extensive cell manipulation, and have low purity. To address these challenges, we report the design and fabrication of a passive, label-free microfluidic device with a unique U-shaped cross-section to separate WBCs from whole blood using hydrodynamic forces that exist in a microchannel with curvilinear geometry. It is shown that the spiral microchannel with a U-shaped cross-section concentrates larger blood cells (e.g., WBCs) in the inner...
Investigating the effect of mixing layer rheology on granular flow over entrainable beds using SPH method
, Article Computers and Geosciences ; Volume 155 , 2021 ; 00983004 (ISSN) ; Manzari, M. T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This paper numerically studies the interaction of a flowing granular material with an entrainable granular bed, while materials are mixed at the interface of two materials. The rheological behavior of this granular mixture is characterized by a generalized viscoplastic model that includes local volume fraction of materials as well as their physical properties, i.e. size, density, and friction angle. Additionally, the effect of the dynamics of entrained bed-type particles on the rheology of the granular mixture is considered. The governing equations of the flow are discretized using the Incompressible Smoothed Particle Hydrodynamics (SPH) method in which mixing of particles can be...