PRCI OBS (V4) – Features and Upgrades Overview
The PRCI On-Bottom Stability software is undergoing substantial technical upgrades. As part of the upgrade, a number of research projects have been executed over the recent years. This paper provides an overview of the latest research with focus on hydrodynamic forces on small diameter pipes as well as efficiency of trenches in shallow water depths.
Small diameter pipes subject to wave and current actions represent large Keulegan Carpenter (KC) numbers with KV>>100. These KC ranges were not included in the DHI model tests that were used to develop the OBS software. Therefore, analysis of cases with KC>100, could produce unreliable results as the data exceed the range of model test data. This paper presents the research that aimed at extending the database to much higher KC numbers using rigorous CFD simulations followed by implementation of the force models in the software.
Another topic of research was to assess the efficiency of the wide trenches in shallow waters and shore approaches. The data of reduction factors for the trenches are limited to āVā shape trenches where pipeline is only partially buried. However, in shore approach areas, the trenches are always wider that the pipe diameter and often much deeper than the pipe diameter.
Although these trenches can be backfilled later, it is crucial to know the protection level that they provide during the installation as well as the period before operation or permanent backfilling. This paper presents the findings of CFD simulation for such trenches.
PRCI OBS (V4.2) – Level 1 Overview
Dr. Kourosh Abdolmaleki demonstrates the web application of the PRCI On-Board Stability (OBS) software, using Level 1 calculations.
The Level 1 analysis tool is intended for simple pipeline stability analyses. It calculates the static stability of an un-trenched pipeline against lateral and vertical displacement under wave and current loading.
PRCI OBS (V4.2) – Level 2 Overview
Dr. Kourosh Abdolmaleki demonstrates the web application of the PRCI On-Board Stability (OBS) software, using Level 2 calculations.
The Level 2 analysis tool is used to determine weight coating requirements based on the latest pipeline hydrodynamic and soil force formulations. It provides the designer a simplified method for estimating pipe embedment and the resulting soil resistance.
PRCI OBS (V4.2) – Level 3 Overview
Dr. Kourosh Abdolmaleki demonstrates the web application of the PRCI On-Board Stability (OBS) software, using Level 3 calculations.
The Level 3 analysis is usually used to check and/or calibrate designs produced using a Level 2 analysis, particularly where the Level 2 assumptions do not accurately represent the actual situation.