scholarly journals AN ESTIMATION OF LONG-PERIOD OSCILATIONS OF MOORED SHIP BY NUMERICAL SIMULATION

2002 ◽  
Vol 18 ◽  
pp. 137-142 ◽  
Author(s):  
Satoru SHIRAISHI ◽  
Haruo YONEYAMA ◽  
Hirakazu SATO ◽  
Kenji SASA
2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.


Author(s):  
Kok Yeow You

In this chapter, the background, analytical formulations, and calibration routines for slot antennas are briefly reviewed. Performance and operating frequency of the slot antenna are strongly dependent on the dimension and shape of the slot or slotted array on the antenna. Nowadays, most antennas are designed using numerical simulation software for accuracy in analysis. However, analytical formulations still play an important role in the pre-design of the antenna due to the numerical simulation which still requires relatively long period of computation time compared to the analytical calculation. The predicted dimension of the antenna from analytical calculations will only require minor adjustment to optimize its performance in numerical simulation. Hence, the time spent for the antenna design can be shortened. Besides the performance of antenna, the antenna calibration process is crucial as well for releasing systematic errors in the antenna measurements. Some one-port calibration methods are described in detail.


2009 ◽  
Vol 36 (3) ◽  
pp. 672-676
Author(s):  
颜爱东 Yan Aidong ◽  
张伟刚 Zhang Weigang ◽  
姜萌 Jiang Meng ◽  
刘卓琳 Liu Zhuolin ◽  
张春艳 Zhang Chunyan ◽  
...  

2008 ◽  
Vol 55 ◽  
pp. 216-220 ◽  
Author(s):  
Tomohiro SHIRAHASHI ◽  
Taro KAKINUMA ◽  
Toshiyuki ASANO ◽  
Michio SATO

Author(s):  
Fanyu Kong ◽  
Xiaokai Shen ◽  
Xufeng Zhang ◽  
Kuanrong Xue ◽  
Shuiqing Zhou ◽  
...  

A new magnetic driving pump with low-NPSHR had been developed to ensure leakage-free for transporting fluid. In hydraulic design, several common measures, according to the equation of cavitation, were applied to lower down the NPSHR of the pump. Moreover, a variable-pitch inducer whose pitch increases gradually was installed at the inlet of impeller. Cavitation performance of the magnetic driving pump and the reasons why the NPSHR was reduced by installing a variable-pitch inducer were analyzed according to the simulation predicted flow field at the pump inlet and inducer. The test of cavitation performance showed that the magnetic driving pump had the excellent cavitation performance, and met the design requirements in flow, head and vibration. The magnetic driving pump presented the reliability after a long period of operation in a petrochemical corporation. Therefore, magnetic driving pumps with low-NPSHR would have a great future in petrochemical, shipping and other important fields.


2013 ◽  
Vol 816-817 ◽  
pp. 294-297 ◽  
Author(s):  
Sheng Wei Yang

In addition to the high cost and long period, the traditional design of the drawing process depends too much on empirical formulas and data. To solve this problem, the paper proposes an ideal design process of the drawing process, which improves the traditional design process bases on CAE and applies FEM software Dynaform. The paper takes a drawing cylinder as an example, which needed 4-stage drawing process, could be improved into 3-stage by the simulation analysis of CAE, as a result , which can reduce the cost and improve the production efficiency.


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