| Author | Ho, Chien-huei |
| Call Number | AIT Thesis no. 927 |
| Subject(s) | Ocean waves
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand |
| Publisher | Asian Institute of Technology |
| Abstract | The fluid flow parameter most closely related to the degree of
bottom sediment motion is the boundary shear stress. Therefore, determination of the boundary shear stress is an integral part of studies where either the inception of motion or the magnitude of transport of
sediments is to be estimated. This thesis is concerned with determination of bottom shear induced by tidal current over nonuniform roughness
boundary. Although in the past years, various methods had been applied to evaluate it in the field. But those methods revealed some difficulties and complications in collecting the data. Besides, not much attempt
had been seen to analyze the problem from the unsteady and nonuniform velocity profiles of the measured current. Therefore the thesis will introduce a simple and practical way to find out the bottom shear acting on a rough boundary provided that the time-average current data at three or four layers over a cross section are available.
This method of analyzing the bottom shear is based on the assumption that the period of the long wave is sufficiently large for one to consider the boundary layer thickness will reach its ceiling, i.e .o = h h is the full water depth. Then shear stresses were calculated from the hourly measured velocity profile on the basis of the logarithmic law existing throughout the whole water depth. Consequently, the frictional coefficient can be obtained from the quadratic stress law. During 1973-1974
a field program was performed at six stations in the Sattahip Bay of the Gulf of Thailand. Three stations were chosen to accomplish this study. The validity of o = h was verified by t he shear wave theory. The
results show good agreement between measured and theoretical velocity profiles for about 60% of the time in one wave cycle. The magnitudes
of bottom shear and frictional coefficient show quite reasonable figures which can fulfil one' s problem study of tidal wave motion. |
| Year | 1978 |
| Type | Thesis |
| School | Student Research Before 1979 |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Thesis (Year <=1979) |
| Chairperson(s) | Suphat Vongvisessomjai |
| Examination Committee(s) | Tawatchai Tingsanchali ;Watanabe, Akira |
| Scholarship Donor(s) | Republic of China |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1978 |