Microwatt energy harvesting by exploiting flow-induced vibration

The green technology approaches by harvesting energy from aerodynamic flowinduced vibrations using a flexible square cylinder is experimentally investigated. The practicability of flow-induced vibration system to supply a sufficient base excitation vibration in microwatt scale is evaluated through a series of wind tunnel tests with different velocities. Test are performed for high Reynolds number 3.9 × 103≤ Re 1.4 × 104 and damping ratio ζ = 0.0052. The experiment setup is able to replicate the pattern of vibration amplitude for isolated square cylinder with previous available study. Then, the experimental setup is used to study the effect of vibration cylinder in harvesting the fluid energy. A prototype of electromagnetic energy harvesting is invented and fabricated to test its performance in the wind tunnel test. Test results reveal that the harnessed power is corresponding to vibration amplitude flow pattern, but the power obtained is much lower than the vibration amplitude due to the power dissipation at the resistor. The best condition for harnessing power is identified at UR = 7.7 where the Karman Vortex-Induced Vibration (KVIV) is the largest

Aerodynamic Analysis on the Effects of Frontal Deflector on a Truck by using Ansys Software

Since the early years of the 20th century, when commercial vehicle mass production began, it has been found that air resistance plays a major factor related to vehicle motion. The main causes of aerodynamic drag for automotive vehicles are the flow separation at the rear end of the vehicles. By reducing the drag force, it is possible to increase the fuel economy. Aerodynamic component i.e. Frontal Deflectors (FD) commonly used on trucks to prevent flow separation. Frontal Deflectors themselves do create the drag, but they also reduce drags by preventing flow separation at downstream. The main aim of this paper is to quantify the effect of frontal deflectors on improving trucks aerodynamics. In this study, the simulation ran for 6 different shapes of FD which acquires different height and different placement of FD that is mounted on the truck from the frontal roof by using ANSYS Fluent software. The design of the truck has been done in SOLIDWORK 2018 and the same design is used for analysis in ANSYS (Fluent). The two-equation models used in this study are 𑘠− 𜀠with applying the Reynolds-averaged Navier Stokes (RANS) equations for the behaviour of fluid flow around the truck. The Reynolds number used is ð‘…ð‘’ = 1.1 × 106.  Based on the result, all the FD’s resulted in a reduction of coefficient of drag. The drag coefficient of all models differs. The velocity streamline acquired is different between the Frontal Deflector models mounted on the truck and the flow structure and vortex formation differs in various pattern formation. FD 4 produces the least value of drag. Hence, the efficiency of the truck improves. Therefore, FD 4 is the best model as the acquired coefficient of drag is 0.508 with the height (15 mm) and placement of (230 mm) is the best FD to be used on a truck. Consequently, the drag reduction percentage of FD 4 compared to the truck without a FD is 32.2%.&nbsp

Aerodynamic Analysis on the Effects of Frontal Deflector on a Truck by using Ansys Software

Since the early years of the 20th century, when commercial vehicle mass production began, it has been found that air resistance plays a major factor related to vehicle motion. The main causes of aerodynamic drag for automotive vehicles are the flow separation at the rear end of the vehicles. By reducing the drag force, it is possible to increase the fuel economy. Aerodynamic component i.e. Frontal Deflectors (FD) commonly used on trucks to prevent flow separation. Frontal Deflectors themselves do create the drag, but they also reduce drags by preventing flow separation at downstream. The main aim of this paper is to quantify the effect of frontal deflectors on improving trucks aerodynamics. In this study, the simulation ran for 6 different shapes of FD which acquires different height and different placement of FD that is mounted on the truck from the frontal roof by using ANSYS Fluent software. The design of the truck has been done in SOLIDWORK 2018 and the same design is used for analysis in ANSYS (Fluent). The two-equation models used in this study are 𑘠− 𜀠with applying the Reynolds-averaged Navier Stokes (RANS) equations for the behaviour of fluid flow around the truck. The Reynolds number used is ð‘…ð‘’ = 1.1 × 106.  Based on the result, all the FD’s resulted in a reduction of coefficient of drag. The drag coefficient of all models differs. The velocity streamline acquired is different between the Frontal Deflector models mounted on the truck and the flow structure and vortex formation differs in various pattern formation. FD 4 produces the least value of drag. Hence, the efficiency of the truck improves. Therefore, FD 4 is the best model as the acquired coefficient of drag is 0.508 with the height (15 mm) and placement of (230 mm) is the best FD to be used on a truck. Consequently, the drag reduction percentage of FD 4 compared to the truck without a FD is 32.2%.&nbsp

Aerodynamic analysis on the effects of frontal deflector on a truck by using ANSYS software

The main causes of aerodynamic drag for automotive vehicles are the flow separation at the rear end of the vehicles. By reducing the drag force, it is possible to increase the fuel economy. Aerodynamic component i.e. Frontal Deflectors (FD) commonly used on trucks to prevent the flow separation. Frontal Deflectors themselves do create the drag, but they also reduce drags by preventing flow separation at downstream. The main aim of this paper is to quantify the effect of frontal deflectors on improving trucks aerodynamics. In this study, the simulation were ran for 6 different shapes of FD which acquires different height and different placement of FD that is mounted on the truck from the frontal roof by using ANSYS Fluent software. The design of the truck has been done in SOLIDWORK 2018 and the same design is used for analysis in ANSYS (Fluent). The two equation models used in this study are k- ε with applying the Reynolds-averaged Navier Stokes (RANS) equations for the behaviour of fluid flow around the truck. The Reynolds number used is Re = 1.1 × 106. Based on the result, all the FD’s resulted in reduction of Cd. The drag coefficient of all FD models differs. The velocity streamline acquired is different between the Frontal Deflector models mounted on the truck and the flow structure and vortex formation differs in various pattern formation. FD 4 produces the least value of drag. Hence, the efficiency of the truck improves. Therefore, FD 4 is the best model as the Cd acquired is 0.508 with the height (15 mm) and placement of (230 mm) is the best FD to be used on a truck. Consequently, the drag reduction percentage of FD 4 compared to the truck without a FD is 32.2%

Flow-induced vibration of a square cylinder and downstream flat plate associated with micro-scale energy harvester

The phenomenon of flow-induced vibration (FIV) over a square cylinder at Reynolds numbers, Re = (3.6–12.5 × 103) is numerically studied. This current study provides a detailed explanation of the behaviour of transverse motion of square cylinder with the mass damping ratio, mζ* = 2.48. The computation of FIV is conducted by numerical simulation based on the Unsteady Reynolds Navier-Stokes (URANS) flow field using OpenFOAM software. The first part of the numerical simulation consists of an isolated square cylinder to validate the solution with previous studies. The computation of FIV with a total number of cells, N = 101,662 have shown a comparable pattern of amplitude curve. The coexistence of vortex-induced vibration (VIV) and galloping is observed for a single isolated cylinder. A downstream flat plate is introduced in the second part of the work. Different gaps separation between the cylinder and flat plate (0.1 ⩽G/D ⩽ 3) are simulated. Based on the amplitude curve against reduced velocities 4 ⩽ UR ⩽ 20, four regimes are identified. According to the power estimation, the optimum gap separation is G/D = 0.1. The harnessed power is higher than a single isolated square cylinder while preserving the robustness for the remote harvesting purpose

The influence of different downstream plate length towards the flow-induced vibration on a square cylinder

Abstract The investigations of flow-induced vibration have been around for decades to solve many engineering problems related to structural element. In a hindsight of advancing technology of microelectronics devices, the implementation of flow-induced vibration for energy harvesting is intrigued. The influence of downstream flat plate to flow-induced vibration experienced by a square cylinder is discussed in this study to surpass the limitation of wind energy due to geographical constraints and climate change. The mechanism of flow-induced vibration experienced by a square cylinder with downstream flat plate is numerically simulated based on the unsteady Reynolds Navier–Stokes (URANS) flow field. The Reynolds number, Re assigned in this study is ranging between $$4.2 \times 10^3$$ 4.2 × 10 3 – $$10.7 \times 10^3$$ 10.7 × 10 3 and the mass damping ratio designated for the square cylinder is $$m^*\zeta$$ m ∗ ζ = 2.48. The influence of three different flat plate lengths $$w/D = 0.5$$ w / D = 0.5 , 1 and 3 is examined. Each case of different flat plate is explored for gap separation between the square cylinder and the plate in the range $$0.5 \leqslant G/D \leqslant 3$$ 0.5 ⩽ G / D ⩽ 3 . Based on the numerical findings, the configuration of cylinder-flat plate with length $$w/D = 1$$ w / D = 1 has shown the highest potential to harvest high energy at comparatively low reduced velocity

Comparative study on energy extraction from vibrating square cylinder

In this paper, the prospect of harvesting energy from flow induced-vibration of a square cylinder is assessed. The extraction of energy from the flow is attained by mounting the square cylinder on a one-degree elastic system with a mass-damping (m*ζ) of 2.75. OpenFOAM®, an open source CFD package is used to model the flow induced motion of the square cylinder. A theoretical formulation to estimate the lift force acting on the square cylinder is derived to confirm the results obtained by the simulation. A good agreement between the results is obtained. The amplitude vibration and lift force are then used to estimate the power induced by the oscillating square cylinder. Energy in the micro scale range can be harvested from this flow induced-vibration system. This type of alternative green energy is suitable for the micro energy harvester system required for sensors in many engineering structure for health monitoring purpose