URANS Simulations of Complex Flows Around a Ship Entering a Lock with Different Speeds
- Qingjie Meng (Shanghai Jiao Tong University) | Decheng Wan (Shanghai Jiao Tong University)
- Document ID
- International Society of Offshore and Polar Engineers
- International Journal of Offshore and Polar Engineering
- Publication Date
- June 2016
- Document Type
- Journal Paper
- 161 - 168
- 2016. The International Society of Offshore and Polar Engineers
- Viscous flow, 12,000-TEU, ship-lock interaction, overset grid, different speed
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In this paper, we investigate the influence of the ship speed on the ship-lock interaction when a 12,000-TEU ship model enters the Third Set of Panama Locks by solving the unsteady Reynolds-averaged Navier-Stokes (RANS) equations in combination with the k-. Shear Stress Transport (SST) turbulence model. An overset grid technique is used to keep grid orthogonality. The effects of the free surface are taken into account. A benchmark test case is designed to validate the present approach to predicting the viscous flow around the ship when it maneuvers into a lock. The accumulation of water in front of the ship during its entry into the lock is observed, which causes the increase in the velocity of the return flow. A set of systematic computations with different ship speeds is then carried out to assess the effects of the ship speed on the ship-lock hydrodynamic interaction. At a higher ship speed, more water is pushed into the lock that results in a higher velocity of the return flow. Furthermore, this will lead to a high risk of ship grounding.
The growing number of large vessels can be used only if a sufficient infrastructure, such as locks, is available. A ship will experience particular hydrodynamic forces caused by the shiplock interaction during its entering maneuver into a lock, which is most critical for large vessels. The hydrodynamic phenomena induced by a lock entry are important for their strong influence on ship motion. The hydrodynamic interaction has a significant influence on a ship’s navigation safety, and the study of this influence is of crucial importance for the safe operation and effective control of ships passing through a lock.
The lock approach will always be accompanied by an effect of shallow water since ships with a very small under-keel clearance are allowed to fully exploit the lock. In addition, ships can also have very small side margins in the lock, and this usually leads to a high blockage. The high blockage may influence the flow along the ship hull and increase the relative speed between the ship and the return flow. Consequently, the frictional resistance increases. Furthermore, the high blockage also causes a so-called piston effect that provokes an accumulation of water during the ship’s entry into the lock. The water piles up inside the lock, resulting in higher pressure resistance.Several methods are used to examine the feasibility of using locks for large vessels. Real scale and model scale tests were carried out, such as Vantorre et al. (2012), which were used to validate the present computations. However, reliable simulations are necessary to examine the infrastructure in an affordable and efficient manner.
|File Size||2 MB||Number of Pages||8|