Erfan Salimipour - Academia.edu (original) (raw)

Papers by Erfan Salimipour

International Journal of Heat and Mass Transfer

Journal of the Brazilian Society of Mechanical Sciences and Engineering

The European Physical Journal Plus, 2021

An active flow control method as CoFlow-Jet (CFJ) is implemented on the NACA 0024 airfoil at the ... more An active flow control method as CoFlow-Jet (CFJ) is implemented on the NACA 0024 airfoil at the chord-based Reynolds number of 1.5×105. For this purpose, an in-house solver based on the Reynolds averaged Navier-Stokes equations in two-dimensional, incompressible and unsteady form with the SST-k-ω turbulence model is prepared. Several levels of jet momentum coefficient (Cμ) are studied to achieve a proper momentum coefficient for each angle of attack (α). The findings demonstrate that at Cμ=0.06, the lift coefficients at low attack angles (up to α =15̊) dramatically increase. Furthermore, the dynamic stall at the given Reynolds number and with the lowered frequency of 0.15 is explored. In the instance of Cμ=0.07, the lift coefficient curve does not show a noticeable stall feature compared to Cμ=0.05, suggesting that a more powerful stronger jet can entirely control the dynamic stall. The impact of raising the Reynolds numbers from 0.5 × 105 to 3 × 105 on this active flow control is ...

The present paper numerically investigates the performance of a Co-Flow Jet (CFJ) on the static a... more The present paper numerically investigates the performance of a Co-Flow Jet (CFJ) on the static and dynamic stall control of the NACA 0024 airfoil at Reynolds number 1.5 × 105. The two-dimensional Reynolds-averaged Navier-Stokes equations are solved using the SST k-ω turbulence model. The results show that the lift coefficients at the low angles of attack (up to α = 15̊) are significantly increased at Cµ = 0.06, however for the higher momentum coefficients, it is not seen an improvement in the aerodynamic characteristics. Also, the dynamic stall for a range of α between 0̊ and 20̊ at the mentioned Reynolds number and with the reduced frequency of 0.15 for two CFJ cases with Cµ = 0.05 and 0.07 are investigated. For the case with Cµ = 0.07, the lift coefficient curve did not present a noticeable stall feature compared to Cµ = 0.05. The effect of this active flow control by increasing the Reynolds numbers from 0.5 × 105 to 3 × 105 is also investigated. At all studied Reynolds numbers, ...

This dataset contains a fortran code along with all the required files. this is a flow and heat t... more This dataset contains a fortran code along with all the required files. this is a flow and heat transfer solver owned by the author.

Original Research Paper Received 31 March 2015 Accepted 19 April 2015 Available Online 09 May 201... more Original Research Paper Received 31 March 2015 Accepted 19 April 2015 Available Online 09 May 2015 In the present paper, two dimensional numerical analysis of the dynamic stall phenomenon associated with unsteady ow around the NACA 0012 airfoil at low Reynolds number (Re 130000) is studied. For this purpose, thin blade with height of 0.005 chord length was placed vertically on the airfoil to control the bursting of the laminar leading edge separation bubble. The numerical simulation of flow is based on discretization of convective flaxes of the turbulent unsteady Navier-stokes equations by second-order Roe’s scheme and an explicit finite volume method in moving coordinate system. Because of the importance of the time dependent parameters in the solution, the second-order time accuracy is applied by dual time stepping approach. Three oscillating patterns with different frequencies and angular amplitudes were used to study the dynamic stall phenomenon. In order to validate the operati...

ARTICLE INFORMATION ABSTRACT Original Research Paper Received 20 September 2016 Accepted 17 Octob... more ARTICLE INFORMATION ABSTRACT Original Research Paper Received 20 September 2016 Accepted 17 October 2016 Available Online 14 November 2016 Flow around a circular cylinder placed in an incompressible uniform stream is investigated via twodimensional numerical simulation in the present study. Some parts of the cylinder are replaced with moving surfaces, which can control the boundary layer growth. Then, the effects of the moving surfaces locations on the power and drag coefficients are studied at various surface speeds. The flow Reynolds number is varied from 60 to 180. To simulate the fluid flow, the unsteady Navier-Stokes equations are solved by a finite volume pressure-velocity coupling method with second-order accuracy in time and space which is called RK-SIMPLER. In order to validate the present written computer code, some results are compared with previous numerical data, and very good agreement is obtained. The results from this study show that some of these surfaces reduce the...

Mojtaba Saei Moghaddam*, Abdolsamad Zarringhalam moghaddam, Nooshin Gholipour Zanjani, Erfan Sali... more Mojtaba Saei Moghaddam*, Abdolsamad Zarringhalam moghaddam, Nooshin Gholipour Zanjani, Erfan Salimipour Department of Chemical Engineering, Quchan Institute of Engineering and Technology, Po.box 9471784686 I.R.Iran Department of Chemical Engineering, Tarbiat Modarres University, Tehran, Po.box 14115-218 I.R.Iran Department of Mechanical Engineering, Quchan Institute of Engineering and Technology, Po.box 9471784686 I.R.Iran Abstract. In this study, diethylene glycol dimethyl ether (Diglyme) was used as an additive to improve fuel properties. The physico-chemical properties and the exhaust emission of the blended fuel and standard diesel were studied. Then exhaust emission of heavy-duty diesel engine have been evaluated experimentally for sole diesel and diglyme-diesel fuel blend. In this section experimental study was carried out on ECE R-96 8-modes cycle. The addition of diglyme to the standard diesel fuel caused significant changes in cetane index, viscosity and flash point tempera...

Total variation diminishing (TVD) scheme is a kind of robust high-resolution approach, which remo... more Total variation diminishing (TVD) scheme is a kind of robust high-resolution approach, which removes the undesirable oscillations generated by numerical solution. The present work proposes a new implementation of the TVD scheme into a density-based semi-implicit finite-volume procedure to solve the inviscid and viscous flow equations. The proposed algorithm uses a simple linearization technique for convective fluxes. In order to enhance the accuracy of the algorithm, a high-resolution TVD scheme is employed in the discretization of the governing equations. This procedure has a simple implementation compared to other explicit and implicit schemes. The present scheme is first examined for some inviscid and viscous steady-state flows at several Mach numbers from subsonic to the supersonic regime. In addition, the inviscid and viscous unsteady flows are simulated and compared with experimental and numerical results, so that an acceptable correspondence was obtained. Results from this st...

دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا یارب : Please cite this article using: S. E. Salim... more دییامن هدافتسا لیذ ترابع زا هلاقم نیا هب عاجرا یارب : Please cite this article using: S. E. Salimipour, A. R. Teymourtash, M. Mamourian, Trajectory Investigation of a Transonic Spherical Projectile under Hop-up Mechanism Using Simulation of Turbulent ThreeDimensional Non-Stationary Flow, Modares Mechanical Engineering, Vol. 17, No. 9, pp. 25-35, 2017 (in Persian) پوه مزیناکم تحت یتوصرذگ یورک هباترپ کی تکرح ریسم یسررب کمک هب پآ هیبش هس یایاپان نایرج یزاس هتفشآ یدعب

A solution procedure is described for determining the two-dimensional and two-degrees of freedom ... more A solution procedure is described for determining the two-dimensional and two-degrees of freedom flutter characteristics for wings at large angles of attack. This procedure requires a simultaneous integration in time of the solid and fluid equations of motion. The fluid relations of motion are the unsteady, compressible Navier-Stokes equations, solved implicitly by second-order Roe approximation scheme in a moving coordinate system. The solid equations of motion were integrated in time by use of fourth-order Runge-kutta method. In this paper, the stall flutter of a rectangular wing with section of NACA 0012 is studied. Therefore, the aeroelastic responses of system were calculated by applying mode shapes for vibrating wing. Then the obtained responses resulted from several changes in L.E. shape of wing are compared. The results showed that these different L.E. shapes cause the changes on oscillating parameters of system. In these changes, applying a camber with 25 deg angle had best...

Journal of Turbulence, 2020

This paper investigates the effects of co-flow jet on the aerodynamic performance of some symmetr... more This paper investigates the effects of co-flow jet on the aerodynamic performance of some symmetric blade sections of wind turbines. The Reynolds number of 1.3 × 10 5 , angles of attack between 0°and 18°a nd momentum coefficients of 0.03, 0.05, and 0.08 are considered for four airfoils of NACA 0012, 0015, 0018, and 0021 as the blade sections. To numerically simulate the fluid flow, the Navier-Stokes equations are solved with a transitional turbulence model. The aerodynamic coefficients along with the lift to drag ratio are calculated and the results are compared with together for the baseline and co-flow jet geometries. The results of the baseline airfoils show that the NACA 0012 and NACA 0015 airfoils generate a larger lift at small angles of attack where the NACA 0018 and NACA 0021 airfoils produce a higher lift at larger angles of attack. Furthermore, the obtained results reveal that applying the co-flow jet has a positive effect on delaying the stall angle and increasing the lift coefficient. The aerodynamic coefficients are also more improved by increasing the thickness once the appropriate momentum coefficient is applied. The results also indicate that the momentum coefficient of 0.05 is sufficient for most of the cases.

Journal of Cleaner Production, 2020

This paper performs an emergy analysis (EmA) to compare two real power plants include a conventio... more This paper performs an emergy analysis (EmA) to compare two real power plants include a conventional natural gas steam power plant (NGPP) with one that burns municipal solid waste (MSWPP). For this purpose, the EmA is used to investigate the sustainability, renewability, environmental impacts, and economic issues. The capacity of the NGPP and MSWPP are 247.5 and 3 MW, respectively. Results from this study show that the percent of renewability (PR) and emergy sustainability index (ESI) of the MSWPP are much more than those of the NGPP. The PR and ESI of the MSWPP are 46.81 and 1.65, while for the NGPP are 5.01 and 0.05, respectively. It is proved that the MSWPP is more efficient and has the better environmental impacts compared to the NGPP. Moreover, a hypothetical MSWPP with the same electricity output of the NGPP is studied using the EmA. A more efficient system with the higher PR and ESI is observed compared to the other case studies. Beside of these advantages, use of the MSW has other benefits such as reducing the greenhouse gases released in the atmosphere, saving fossil fuels, low land area required compared to the landfill, speed and ease of disposal, and production of clean and useful ash.

International Journal of Thermal Sciences, 2020

The present paper numerically investigates the laminar, two-dimensional and horizontal flow aroun... more The present paper numerically investigates the laminar, two-dimensional and horizontal flow around a horizontal isothermal rotating cylinder under the buoyancy effect. To study the buoyancy effect, a range of Grashof numbers from 0 to 12 � 10 4 is used, and to check the effect of the cylinder rotation, the ratio of the rotational speed to the free-stream velocity between À 4.5 and 4.5 is applied. The simulation is carried out at the Reynolds number of 200 and the Prandtl number of 0.7. To simulate the fluid flow, the Navier-Stokes equations are numerically solved using a finite-volume scheme. Results show that the interaction of the main stream with the rotation and buoyancy can alter the flow field and heat transfer characteristics such as flow pattern, surface pressure distribution, lift and drag coefficients, and Nusselt number. The clockwise (cw) rotation decreases the amplitude of oscillations in the flow compared to the counterclockwise (ccw) rotation. In ccw rotation, as the Grashof number increases, the mean lift coefficient increases; while in cw rotation, increase in the Grashof number reduces the mean lift coefficient. Moreover, in terms of Grashof numbers ranging between 8 � 10 4 and 12 � 10 4 , the Nusselt number is almost unchanged.

Ocean Engineering, 2020

In the present study, the effects of a moving surface on the aerodynamic characteristics of an of... more In the present study, the effects of a moving surface on the aerodynamic characteristics of an offshore wind turbine blade were numerically examined. The S809 airfoil was considered as the blade section. A part of the airfoil surface was replaced with a moving surface as a flow control mechanism. To achieve the highest mechanical performance of the airfoil at each angle of attack, the effects of location and speed of the moving surface on the flow characteristics were studied. The flow simulation was carried out using a computational fluid dynamics technique. The results of this study indicated that the use of a moving surface with appropriate speed and location could enhance the airfoil performance. As the angle of attack increased, a stronger moving surface was needed. The performance improvement for α ¼ 8 � , 11 � , 14 � , and 17 � was 30%, 62%, 131%, and 152%, respectively. In addition, the performance of a three-bladed horizontal axis wind turbine was numerically analyzed in the range of tip speed ratio, 4 � TSR � 9. It was observed that the moving surface significantly improved the torque and power generated by the turbine, especially at low TSRs. This improvement was over 90% for TSR < 5.

Ocean Engineering, 2019

A two-dimensional simulation of the laminar flow past a circular cylinder is investigated, in thi... more A two-dimensional simulation of the laminar flow past a circular cylinder is investigated, in this study. To control the boundary layer growth, a pair of moving surfaces with streamwise (positive) motion is mounted on different locations of the upper and lower surfaces of the cylinder. The effects of the surface locations on the power and drag coefficients and the vortex shedding state are studied at several moving surface speeds. The Reynolds number based on the cylinder diameter is varied between 60 and 180. The flow simulation is performed by a solution of the unsteady Navier-Stokes equations using a pressure-velocity coupling method. To integrate the momentum equations, a four-stage Runge-Kutta scheme with second-order accuracy in time and space is used. Some results are compared with previous experimental and numerical data. The results from this study indicate that the moving surfaces can eliminate the vortex shedding so that the flow achieves a steady state for the abovementioned range of Reynolds number. It is also found that some of these surfaces reduce the drag coefficient and the total power requirements of the system motion. Moreover, the optimum location and the speed of the surfaces corresponding to the minimum power coefficient are obtained.