scholarly journals Experimental and numerical analysis of the performance and wake of a scale–model horizontal axis marine hydrokinetic turbine

2017 ◽  
Vol 9 (4) ◽  
pp. 044504 ◽  
Author(s):  
Teymour Javaherchi ◽  
Nick Stelzenmuller ◽  
Alberto Aliseda
Keyword(s):  
Numerical Analysis ◽  
Horizontal Axis ◽  
Scale Model ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

Passive Pitch Control of Horizontal Axis Marine Hydrokinetic Turbine Blades

2014 ◽  
Author(s):  
Michael R. Motley ◽  
Ramona B. Barber
Keyword(s):  
Alternative Energy ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Pitch Control ◽  
Fluid Forces ◽  
Hydrokinetic Turbines ◽  
Energy Technologies ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

As the need for clean and renewable energy becomes greater, alternative energy technologies are becoming more and more prevalent. To that end, there has been a recent increase in research on marine hydrokinetic turbines to assess their potential as a reliable source of energy production and to expedite their implementation. These turbines are typically constructed from fiber reinforced composites and are subject to large, dynamic fluid forces. One of the benefits of composite materials is that the bend-twist deformation behavior can be hydroelastically tailored such that the blades are able to passively change their pitch to adapt to the surrounding flow, creating a nearly instantaneous control mechanism that can improve system performance over the expected range of operating conditions. These improvements include increasing energy capture, reducing instabilities, and improving structural performance. Practical constraints, however, lead to limitations in the scope of these performance enhancements and create tradeoffs between various benefits that can be achieved. This paper presents a numerical investigation into the capability of passive pitch control and combined active/passive pitch control to modify the performance of horizontal axis marine turbines with proper consideration of practical restrictions.

Modeling the wake dynamics of a marine hydrokinetic turbine using different actuator representations

2021 ◽  
Vol 222 ◽  
pp. 108584
Author(s):  
Jorge Sandoval ◽  
Karina Soto-Rivas ◽  
Clemente Gotelli ◽  
Cristián Escauriaza
Keyword(s):  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

Simulation of a Free Standing Riser Model and Validation With Experimental Results

2014 ◽  
Author(s):  
Marcio Yamamoto ◽  
Sotaro Masanobu ◽  
Satoru Takano ◽  
Shigeo Kanada ◽  
Tomo Fujiwara ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Previous Experiment ◽  
Numerical Results ◽  
Experimental Results ◽  
Previous Article ◽  
Scale Model ◽  
Analysis Software ◽  
Free Standing ◽  
Reduced Scale

In this article, we present the numerical analysis of a Free Standing Riser. The numerical simulation was carried out using a commercial riser analysis software suit. The numerical model’s dimensions were the same of a 1/70 reduced scale model deployed in a previous experiment. The numerical results were compared with experimental results presented in a previous article [1]. Discussion about the model and limitations of the numerical analysis is included.

scholarly journals Experimental and Numerical Study of Pre-Swirl Stators PSS

2020 ◽  
Vol 8 (1) ◽  
pp. 47 ◽  
Author(s):  
Kourosh Koushan ◽  
Vladimir Krasilnikov ◽  
Marco Nataletti ◽  
Lucia Sileo ◽  
Silas Spence
Keyword(s):  
Numerical Analysis ◽  
Energy Saving ◽  
Scale Effect ◽  
Financial Incentives ◽  
Numerical Study ◽  
Considerable Improvement ◽  
Scale Model ◽  
Propulsion Efficiency ◽  
Wake Field ◽  
Additional Resistance

Energy saving within shipping is gaining more attention due to environmental awareness, financial incentives, and, most importantly, new regional and international rules, which limit the acceptable emission from the ships considerably. One of the measures is installation of energy saving devices (ESD). One type of such a device, known as pre-swirl stator (PSS), consists of a number (usually 3 to 5) of fins, which are mounted right in front of the propeller. By modifying the inflow and swirl into the propeller, the fins of a PSS have the possibility to increase the total propulsion efficiency. However, at the same time, they may introduce additional resistance either due to changes in pressure distribution over the aft ship or due to its own resistance of fins. In this paper, the authors present experimental and numerical investigation of a PSS for a chemical tanker. Numerical analysis of the vessel with and without PSS is performed in the model and full scale. Model testing is performed with and without PSS to verify the power savings predicted numerically. Among other quantities, 3D wake field behind the hull is densely measured at different planes, starting from the PSS plane to the rudder stock plane. 3D wake measurements are also conducted with a running propeller. The measurements show considerable improvement in the performance of the vessel fitted with PSS. On the numerical side, analyses show that scale effect plays an important role in the ESD performance. Investigation of the scale effect on the vessel equipped with an ESD provides new insight for the community, which is investing more into the development of energy saving devices, and it offers valuable information for the elaboration of scaling procedures for such vessels.

Evaluation of bridge support condition using bridge responses

2018 ◽  
Vol 18 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Young-Soo Park ◽  
Sehoon Kim ◽  
Namgyu Kim ◽  
Jong-Jae Lee
Keyword(s):  
Sensitivity Analysis ◽  
Numerical Analysis ◽  
Field Test ◽  
Laboratory Tests ◽  
Spring Constant ◽  
Scale Model ◽  
Support Condition ◽  
Bridge Responses ◽  
Spring Constants

This article presents a method for evaluating the support condition of bridges. This is done by representing the aging and deteriorated supports as rotation springs with equivalent spring constants. Sensitivity analysis was performed to obtain a relationship between the spring constant and the bridge responses (deflections/slopes). From this relationship, measured bridge responses can be used to estimate the equivalent spring constants through interpolation. Numerical analysis was performed to check whether the method can be used to calculate equivalent spring constants. Then, the method was verified by performing laboratory tests on a scale model bridge and field test on an actual bridge. In both tests, spring constants were estimated using the proposed method and then verified by calculating the displacements and frequencies and comparing them to the measured values.

scholarly journals Noise Characteristics Analysis of the Horizontal Axis Hydrokinetic Turbine Designed for Unmanned Underwater Mooring Platforms

2019 ◽  
Vol 7 (12) ◽  
pp. 465 ◽  
Author(s):  
Zhigao Dang ◽  
Zhaoyong Mao ◽  
Baowei Song ◽  
Wenlong Tian
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Pressure Fluctuations ◽  
Noise Pollution ◽  
Horizontal Axis ◽  
Acoustic Analogy ◽  
Noise Emission ◽  
Suction Surface ◽  
Noise Characteristics ◽  
Hydrokinetic Turbine

Operating horizontal axis hydrokinetic turbine (HAHT) generates noise affecting the ocean environment adversely. Therefore, it is essential to determine the noise characteristics of such types of HAHT, as large-scale turbine sets would release more noise pollution to the ocean. Like other rotating machinery, the hydrodynamic noise generated by the rotating turbine has been known to be the most important noise source. In the present work, the transient turbulent flow field of the HAHT is obtained by incompressible large eddy simulation, thereafter, the Ffowcs Williams and Hawkings acoustic analogy formulation is carried out to predict the noise generated from the pressure fluctuations of the blade surface. The coefficient of power is compared with the experimental results, with a good agreement being achieved. It is seen from the pressure contours that the 80% span of the blade has the most severe pressure fluctuations, which concentrate on the region of leading the edge of the airfoil and the suction surface of the airfoil. Then, the noise characteristics around a single turbine are systematically studied, in accordance with the results of the flow field. The noise characteristics around the whole turbine are also investigated to determine the directionality of the noise emission of HAHT.

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