scholarly journals EXPERIMENTAL STUDY ON SPEED REDUCTION EFFECT BY SEQUENCE DESIGN

2010 ◽  
Vol 66 (1) ◽  
pp. 27-39
Author(s):  
Yukio ADACHI ◽  
Yasuo FUJII ◽  
Dai TAMAGAWA ◽  
Yasuyuki IWASATO ◽  
Koichiro YAMADA ◽  
...  
Keyword(s):  
Experimental Study ◽  
Sequence Design ◽  
Speed Reduction ◽  
Reduction Effect

scholarly journals Airflow Characteristics According to the Change in the Height and Porous Rate of Building Roofs for Efficient Installation of Small Wind Power Generators

2021 ◽  
Vol 13 (10) ◽  
pp. 5688
Author(s):  
Jangyoul You ◽  
Kipyo You ◽  
Minwoo Park ◽  
Changhee Lee
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Turbulence Intensity ◽  
Flow Characteristics ◽  
High Porosity ◽  
Power Generators ◽  
Speed Reduction ◽  
Reduction Effect ◽  
Wind Power Generators ◽  
The Impact

In this paper, the air flow characteristics and the impact of wind power generators were analyzed according to the porosity and height of the parapet installed in the rooftop layer. The wind speed at the top was decreasing as the parapet was installed. However, the wind speed reduction effect was decreasing as the porosity rate increased. In addition, the increase in porosity significantly reduced turbulence intensity and reduced it by up to 40% compared to no railing. In the case of parapets with sufficient porosity, the effect of reducing turbulence intensity was also increased as the height increased. Therefore, it was confirmed that sufficient parapet height and high porosity reduce the effect of reducing wind speed by parapets and significantly reducing the turbulence intensity, which can provide homogeneous wind speed during installation of wind power generators.

scholarly journals 710 Experimental Study on Friction Drag Reduction Effect of Flexible Tube(1)

2006 ◽  
Vol 2006 (0) ◽  
pp. _710-a_
Author(s):  
Zhigang GAO ◽  
Masatomo OHWAKI ◽  
Motoyuki ITOH ◽  
Shinji TAMANO ◽  
Kazuhiko YOKOTA
Keyword(s):  
Experimental Study ◽  
Drag Reduction ◽  
Friction Drag ◽  
Flexible Tube ◽  
Reduction Effect ◽  
Friction Drag Reduction

The Experimental Study of the Magnetic Fluid Damper Based on the Principle of Second-Order Buoyancy

2012 ◽  
Vol 512-515 ◽  
pp. 1459-1463 ◽  
Author(s):  
Yi Ding ◽  
De Cai Li ◽  
Qing Lei Wang ◽  
Hai Na Zhang ◽  
Zhi Li Zhang
Keyword(s):  
Experimental Study ◽  
Magnetic Fluid ◽  
Second Order ◽  
Test Rig ◽  
Damping Effect ◽  
Fluid Damper ◽  
Reduction Effect ◽  
Set Up ◽  
The Relationship

Two different structure of dampers based on the principle of second-order buoyancy were designed in this paper. In order to verify the reduction of the vibration, a test rig was set up. On the test rig, the reduction effect of two different dampers was studied by adjusting the amount of the magnetic fluid. The experiment results indicate the relationship between the damping effect of magnetic fluid damper and the amount of magnetic fluid and this analysis result is benefit to the design of the dampers.

Experimental Study on Drag-Reduction Effect of a New Sinusoidal Riblet

2012 ◽  
Author(s):  
Monami Sasamori ◽  
Kaoru Iwamoto ◽  
Akira Murata
Keyword(s):  
Experimental Study ◽  
Drag Reduction ◽  
Flat Surface ◽  
Reynolds Shear Stress ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Physical Mechanisms ◽  
Image Velocimetry ◽  
Reduction Effect ◽  
Riblet Surface

An experimental study of a new three-dimensional (3-D) riblet has been carried out. The lateral spacing of our 3-D riblet surface is sinusoidally varied in the streamwise direction (see Fig. 3). In the comparison of the optimal two-dimensional (2-D) blade riblet which shows 9.9% drag reduction rate [1], the riblet height, thickness and averaged lateral spacing are respectively 0.83, 5 and 2.5 times larger than those of the optimal 2-D riblet in wall units. The net drag reduction rate of 11.7% has been confirmed in a low-speed wind channel at the bulk Reynolds number of 3400. The flow structure over the 3-D riblet mounted a wall was also analyzed in the velocity field by using 2-D Particle Image Velocimetry and was compared with the corresponding flow over the flat surface in an attempt to identify the physical mechanisms for the drag reduction. The normal turbulent intensities on the present riblet are almost same as those of the flat surface, whereas the Reynolds shear stress is much decreased, and especially becomes negative near the riblet height. These are different phenomena from those of all the previous riblets [1–7].

scholarly journals Windbreak and airflow performance of different synthetic shrub designs based on wind tunnel experiments

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244213
Author(s):  
Xia Pan ◽  
Zhenyi Wang ◽  
Yong Gao ◽  
Zhengcai Zhang ◽  
Zhongjv Meng ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Erosion ◽  
Protective Effects ◽  
Wind Tunnel Experiments ◽  
Speed Reduction ◽  
Environmental Threats ◽  
Wind Speeds ◽  
Airflow Field ◽  
Reduction Effect

Wind erosion has gained increasing attention as one of the most serious global ecological and environmental threats. Windbreaks are effective at decreasing wind erosion by reducing wind speed to protect crops, livestock, and farmsteads, while providing wildlife habitats. Synthetic shrubs can act as novel windbreaks; however, there is limited knowledge on how their design affects wind speed. This study determined the protective effects (airflow field and sheltering efficiency) based on the design of synthetic shrubs in a wind tunnel. Broom-shaped synthetic shrubs weakened the wind speeds mainly at the middle and upper parts of the shrubs (5–14 cm), while for hemisphere-shaped shrubs this effect was greatest near their bases (below 4 cm) and least in the middle and upper parts (7–14 cm). Spindle-shaped synthetic shrubs provided the best reduction effect in wind range and strength. Moreover, the wind speed reduction ratio decreased with improved wind speeds and ranged from 26.25 cm (between the second and third rows) to 52.5 cm (after the third row). These results provide strong evidence that synthetic shrubs should be considered to decrease wind speed and prevent wind erosion.

scholarly journals Influence of Wider Longitudinal Road Markings on Vehicle Speeds in Two-Lane Rural Highways

2020 ◽  
Vol 12 (20) ◽  
pp. 8305
Author(s):  
Francisco Calvo-Poyo ◽  
Juan de Oña ◽  
Laura Garach Morcillo ◽  
José Navarro-Moreno
Keyword(s):  
Road Safety ◽  
Traffic Accidents ◽  
Road Transport ◽  
Traffic Volume ◽  
Vehicle Speed ◽  
Rural Highways ◽  
Speed Reduction ◽  
Wide Road ◽  
Reduction Effect ◽  
Working Day

Longitudinal road markings are a valuable aid in driving guidance. An increase in their width may influence driving and, therefore, road safety. Wider road markings generate a perception of a narrowing lane, which may induct drivers to reduce speed. The present study tries to verify if an increased width of longitudinal road markings actually helps one to drive more slowly, and consequently leads to enhanced road safety. For this purpose, three curves with reduced visibility were selected and driving speed was measured with normal and modified (wider) longitudinal road markings. The results showed a speed reduction effect of around 3.1% with wide road markings. The speed-reducing effect of wide marks was greater during weekends and with more intense traffic volume, while it was slightly attenuated by night. Finally, the calculation of some standard cases on a working day, and considering average traffic volume, gave the following speed reductions during the day and at night, respectively: for light vehicles, 2.24% and 1.96%; for heavy vehicles, 2.46% and 2.15%. In view of the results obtained, it may be said that using wide road markings can help reduce vehicle speed, thereby contributing to reduced traffic accidents and making road transport more sustainable.

Walking speed reduction rates at intersections while wayfinding indoors: An experimental study

2020 ◽  
Author(s):  
Young‐Hoon Bae ◽  
Young‐Chan Kim ◽  
Ryun‐Seok Oh ◽  
Jong‐Yeong Son ◽  
Won‐Hwa Hong ◽  
...  
Keyword(s):  
Experimental Study ◽  
Walking Speed ◽  
Speed Reduction
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