مطالعهی آزمایشگاهی الگوی آبشستگی ناشی از استقرار پایههای دوتایی همگرا و واگرا و همراستا با جریان در موقعیتهای مختلف قوس ۱۸۰ درجه
| Autor: | M. Moosaei, M. Vaghefi, S.H. Meraji |
|---|---|
| Jazyk: | perština |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | مهندسی عمران شریف, Vol 33.2, Iss 4.1, Pp 61-70 (2018) |
| Druh dokumentu: | article |
| ISSN: | 2676-4768 2676-4776 |
| DOI: | 10.24200/j30.2018.1264 |
| Popis: | One of the issues in river engineering is bridge protection in a way that bridges suffer the minimum damage during a flood. In many cases, due to the limitations, bridges are constructed on a river bend. The purpose of this research is to investigate the effect of constructing convergent and divergent (V-shaped \& A-shaped) coupled bridge piers and their position in parallel to the flow on a steep 180-degree bend bed topography. This research was performed on a laboratory channel at Persian Gulf University of Bushehr, Iran. The channel has a width of 1 meter, and a steep bend with a central radius to channel width ratio of 2 and a 180-degree bend. In the upstream and downstream of the bed, there are direct routes with lengths of 6.5 and 5.1 meters, respectively. For the experiments, PVC piers with 5 cm diameter a 21-degree angle to the vertical axis, materials with an average diameter of 1.5 mm and standard deviation of 1.14 were used. All the experiments were performed with flow velocity to critical velocity ratio of 0.98 (U/Uc=0.98) and constant depth of 18 cm at the beginning of the bend and 70 l/s discharge. The results show that the maximum depth of the scour hole occurs adjacent to the V-shaped coupled piers established at the position of 90 degree. By changing the piers from V-shaped to A-shaped at 60 and 90 degrees positions, the maximum scour hole is transfered from the adjacency of the upstream pier to the adjacency of the downstream pier, and by changing the position of the piers from the bend's upstream towards the downstream, the development of the maximum scour hole decreases. The highest scour depths were measured in the main hole and the second scour hole and also the highest sedimentation were measured as 0.97, 0.93 and 0.58 times the flow depth at the starting point of the bend respectively. In this paper, the results are discussed and analyzed. |
| Databáze: | Directory of Open Access Journals |
| Externí odkaz: |
|