The influence of time step setting on the CFD simulation result of vertical axis tidal current turbine

Satrio, Dendy; Utama, I Ketut Aria Pria; Mukhtasor, MEng Ir.

doi:10.15282/jmes.12.1.2018.9.0303

Cited by 31 publications

(13 citation statements)

References 9 publications

(22 reference statements)

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“…In a certain case, the thin airfoil can be used as a helicopter rotor [7]. Satrio et al [8] explored the performance of the Darrieus turbine using CFD solver and then compared it to the experimental result.…”

Section: Introductionmentioning

confidence: 99%

Effect of Savonius blade height on the performance of a hybrid Darrieus-Savonius wind turbine

Puspitasari¹,

Sahim²

2019

JMES

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A vertical hybrid turbine commonly consists of a Darrieus and Savonius rotor where the Savonius is inside Darrieus turbine. This paper describes the experimental study of hybrid Darrieus-Savonius wind turbines by variation in Savonius blade height. In this case, the effect of the blade height of the Savonius blade was studied experimentally in a subsonic wind tunnel. The effect of the height of a Savonius blade relative to that of Darrieus called blade height ratios δ was investigated to know the hybrid turbine performance. The performance is represented by power and torque coefficient. The result shows that the hybrid turbine with height ratio greater than unity δ = 1.4 gives the highest power CP = 0.20 and torque coefficient CT = 0.129. It is investigated that the torque and the power coefficient have a higher value than that of Darrieus turbine, in which the increase in power and torque coefficient are 48% and 29%, respectively. This hybrid wind turbine with a blade height ratio greater than unity can be considered as an important variable in the wind turbine construction.

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Section: Introductionmentioning

confidence: 99%

Effect of Savonius blade height on the performance of a hybrid Darrieus-Savonius wind turbine

Puspitasari¹,

Sahim²

2019

JMES

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“…The co-simulation algorithm needs to automatically use the data from the CFD to be used in the mechanical problem as an input (the pressure field and shear loads). Since the geometry is changing from the initial condition for each instant of time (which impacts on the results calculated for the suction), an updated geometry is created automatically for each time step [21], where the clot displacement and deformation are the resultant of the previous time step.…”

Section: Experiments Runmentioning

confidence: 99%

Thrombectomy aspiration device geometry optimization for removal of blood clots in cerebral vessels

Talayero¹,

Romero²,

Pearce³

et al. 2020

JMES

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A study involving the removal of blood clots in cerebral vessels by aspiration thrombectomy is presented. A robust design for the distal end geometry of a catheter is obtained that, together with adequate suction conditions, could avoid potential damage in the artery or fragmentation the thrombus. The optimization process of the parameters is undertaken by a Design of Experiments (DOE) that has been prepared based on Robust Design theories. In particular, 27 experiments are run for one factor at 9 levels (catheter geometry) and up to 9 factors at 3 levels. The experiments are formulated with virtual models that are solved with computing tools. Co-simulation between Computer Fluid Dynamics (CFD) and Finite Elements Method (FEM) structural analysis was used to obtain the suction conditions and the behavior of the blood clot during the intervention process. By comparing the results of the 27 experiments, the highest values of the suctioning force are obtained for a hole pattern based catheter design, that also gives the lowest risk for clot damage (based on the stress value obtained). Direct aspiration and designs based on conical catheter distal ends, give less robust solutions (results are not stable when the conditions of the environment change). Our study investigated the distance between the catheter and the clot, and it was noted that if the catheter was far from the clot, the suction generated a vessel narrowing and consequent potential damage. Up to 90 kPa could be applied when suctioning at a maximum distance equal to the diameter of the vessel between the distal end of the catheter and the proximal end of the clot. A maximum suctioning force of 0,514N was achieved without damage to the artery or the clot. This research enables us to determine and use the most representative parameters and geometries to be tested in in-vitro and in-vivo experiments. In this virtual study, hypothesizes are assumed with regard to the material properties, but the robustness of the design process allows to expect similar results in future in-vitro and in-vivo tests.

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“…The mesh near to the foil was refined as depicted in Figure 6, which shows a zoomed-in view to explain that this location required this treatment for resolving the boundary layer flows. The inflation layer strategy was implemented, with the non-dimensional wall distance (y+) value for the first mesh being 0.99 regarding the Reynolds number value from the experiment and according to experience from previous studies [15,17,21]. The first mesh height was 1.13 10-4 m as calculated with the y+ equation.…”

Section: Meshing Strategymentioning

confidence: 99%

Numerical simulation of foil with leading-edge tubercle for vertical-axis tidal-current turbine

Utama¹,

Satrio²,

Mukhtasor³

et al. 2020

JMES

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The main disadvantage of the vertical-axis turbine is its low coefficient of performance. The purpose of this work was to propose a method to improve this performance by investigating the hydrodynamic forces and the flow-field of a foil that was modified with a sinusoidal leading-edge tubercle. NACA 63(4)021 was chosen as the original foil since it has a symmetrical profile that is suitable for use on a vertical-axis tidal-current turbine. The study was conducted using a numerical simulation method with ANSYS-CFX Computational Fluid Dynamics (CFD) code to solve the incompressible Reynolds-Averaged Navier-Stokes (RANS) equations. Firstly, the simulation results of the original foil were validated with available experimental data. Secondly, the modified foils, with three configurations of tubercles, were modelled. From the simulation results, the tubercle foils, when compared with the original foil, had similar lift performances at low Angles of Attack (0-8 degrees of AoA), lower lift performances at medium AoA (8-19 degrees) and higher lift performances at high AoA (19-32 degrees). A tubercle foil with Height/Chord (H/C) of 0.05 can maintain the static stall condition until 32 degrees. Therefore, a vertical-axis turbine with tubercle-blades provides an opportunity to increase its performance by extending the operational range for extracting energy in the dynamic stall condition.

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The influence of time step setting on the CFD simulation result of vertical axis tidal current turbine

Cited by 31 publications

References 9 publications

Effect of Savonius blade height on the performance of a hybrid Darrieus-Savonius wind turbine

Effect of Savonius blade height on the performance of a hybrid Darrieus-Savonius wind turbine

Thrombectomy aspiration device geometry optimization for removal of blood clots in cerebral vessels

Numerical simulation of foil with leading-edge tubercle for vertical-axis tidal-current turbine

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