Variation of tree crown height effects on flow behavior around finite vegetation

Abstract

Finite-length vegetation has been previously studied for its ability to provide resistance against the tsunami by using just the trunk section of the tree stand structures. However, investigating the resilience of the vegetation while taking the crown section into account is yet unknown. Using a limited emergent vegetation model (EVM), this research examined the impact of changing the tree crown heights on the flow structure behavior between the vegetation and its surrounding gap region. Experimental variables included such as tree crown height ( in which is the crown height from the ground surface and is the total tree height), vegetation width to length ratio (W/L), and the initial Froude number condition , which ranged between 0.67 and 0.76. The outcomes demonstrated that, when the vegetation width to length ratio was small, the crown height ratio ( < 0.3) significantly reduced the velocity and fluid force behind the vegetation patch region as compared to no crown (NC) and highest crown height ratio ( > 0.3). On the other hand, the effect of crown cases in the small vegetation patch did not increase the velocity and fluid force in the gap region in comparison with NC. Whereas the increased width of the vegetation patch along with the lower crown height ratio ( < 0.4) further decreased the velocity and fluid force behind the vegetation patch but the increased width of the vegetation patch in combination with the lower crown height ratio increased the velocity and fluid force in the surrounding gap region as compared to its NC case.