Posted on December 3, 2020
VICKSBURG, Miss. — In contingency operations, the Modular Causeway System (MCS), an assembly of floating modules, is often used for loading and unloading supplies and equipment from ship to shore. The U.S. Transportation Command has enlisted the help of researchers at the U.S. Army Engineer Research and Development Center (ERDC) to numerically model the MCS and provide data that will aid in expanding the guidance to increase safety and efficiency for the warfighter.
In any military operation, logistical support is dependent on several variables, including environmental conditions, infrastructure and combatant constraints. Moving personnel, supplies and equipment can be especially complex during Joint Logistics Over-the-Shore operations, or JLOTS, when a modern deep-water port is unavailable, inadequate or damaged.
JLOTS operations have been a part of the U.S. military’s strategy since its inception and were used in theaters such as Vietnam, Grenada, Panama and Iraq. They provide required operational maneuver capabilities in areas of anti-access or area denial (A2/AD) environments and allow for movement of a heavy force.
The MCS can be joined together in various configurations. One important configuration is the Trident pier, as it offers a roll-on/roll-off berth for vessels that are directly connected to the shore. It is often utilized in austere environments or to supplement existing discharge facilities due to its high throughput capacity.
“We are providing additional data for the warfighter to help shape the guidance on determining beforehand where and when to deploy the MCS,” said Dr. Gaurav Savant, a research hydraulic engineer with the ERDC’s Coastal and Hydraulics Laboratory and lead for modeling the MCS. “We are going to provide states of the MCS when it’s in the ocean, in the process of going on the beach and when it actually hits the beach.”
“By developing a high-fidelity computational fluid dynamics (CFD) model for the MCS, we can provide planners precise knowledge of Trident pier behavior under various operating conditions to better quantify system limitations and support improved throughput, operational time and debarkation selection,” he said.
Current guidance states that all MCS configurations must cease operation at sea state three due to unsafe heave that may produce structural damage. “But sea states do not account for currents — like a rip current that might occur close to the shore,” said Savant. “We don’t want to deploy the MCS in operations or in theater and then find out there’s going to be some really high currents that are going to stop operations — that’s the worst case.”
Savant and his team are using an in-house, CHL-developed software called Proteus, along with the open source Chrono toolkit, to simulate how the MCS would respond to changing seas, winds, waves and currents. The dynamic linkage of Proteus and Chrono allows ERDC to computationally determine the behavior of the MCS without physically observing this behavior in the field, thereby reducing program costs.
“ERDC is at the forefront of development and application of state-of-the-art CFD models to investigate the interaction between fluids and structures,” said Savant. “By testing numerically on the supercomputers, we are able to adjust the numerics to simulate exactly what might be happening in the field.”
“The biggest challenge has been configuring the software to accurately depict how the various joints of the MCS modules respond to the changing sea,” he said. “If you don’t have the joints right, the behavior is going to be wrong, which could not only be inefficient but deadly. Getting those joints and the forces that act on those joints correct has been a challenge.”
ERDC researchers are also testing the stability of the Trident pier during its stabbing action when securing it into the beach. “ERDC is computationally simulating this and other conditions under various sea states and hydrologic forcings to populate a database that the warfighter can use to proactively determine the stability of the pier,” said Savant. “ERDC simulations will also help inform the pier configuration and debarkation site selection.”
The results from the simulations are being housed in an access-controlled web application. This application will allow the warfighter to query the simulation database and obtain an analysis of the pier response prior to initialization of operations.
“We have gotten some great feedback on how to transition this technology to the field,” said Savant. “We are going to create an app that allows the warfighter in the field to type in the approximate current conditions and receive a go or no-go situation response.”
“The technology we are using can easily transition to other Department of Defense agencies,” he said. “CFD modeling can provide significant cost and time savings and is essential for joint operations in any A2/AD environment.”
Source: erdc.usace.army.mil
