English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the zaia usage as premium feature

ZAIA

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the access of premium content as premium feature

Premium Content

Zendy Tools

Zendy Open

The friction for sliding objects over partially water-saturated granular materials is investigated as a function of the water volume fraction. We find that ploughing friction is the main sliding mechanism: The slider leaves a deep trace in the sand after its passage. In line with previous research and everyday experience, we find that the friction force varies nonmonotonically with the water volume fraction. The addition of a small amount of water makes the friction force sharply drop, whereas too much added water causes the friction force to increase again. We present a ploughing model that quantitatively reproduces the nonmonotonic variation of the friction force as a function of water volume fraction without adjustable parameters. In this model, the yield stress of the water-sand mixture controls the depth to which the hemisphere sinks into the sand and the force that is required to plough through the water-sand mixture. We show that the model can also be used for other ploughing friction experiments, such as an ice skate that leaves a ploughing track on ice.

Ploughing friction on wet and dry sand