Volume contraction-induced fluidization would allow for the design of compact anchoring technologies applicable to various industries. A razor-clam based system can be used for underwater robot tethering, oil rig mooring, down-hole tool transportation, and underwater mine neutralization.
Existing anchoring technologies have limited applications due to their high energy dependence and also to the transportation difficulties that arise from their large size and heavy weight. This invention would allow for an efficient means of burrowing through underwater granular substrates that is both reversible and dynamic. Current technologies pump water into the substrate to facilitate penetration; however, it is expensive and requires a significant amount of energy. This method removes pumping water from the process and therefore decreases the amount of energy expended. By employing a process found in nature, this technology allows for the design of ultra-efficient burrowing machines for a variety of sizes, substrates, and applications.
Razor clams are able to reduce drag on their body by nearly 4 orders of magnitude compared to penetrating packed, static soil by quickly reducing the volume of their bodies to fluidize the substrate surrounding their shell. Experiments have shown that drag reduction due to fluidization increases with greater depth, greater void fraction, and reduced velocity. As a result, the razor clam is able to quickly burrow through granular substrates and expends very little energy during the process. This invention uses a similar technique of volume contraction and localized fluidization to efficiently move through granular substrates. A razor clam-based anchor will provide significant performance advantages over existing technologies.
- Can attach to a variety of seabeds (silt, mud, sand, loose gravel, etc.)