Amirshahi, Seyed Mohammad

Near bed turbulence, plays an important role in the entrainment and horizontal and vertical mixing of suspended sediment. Understanding this interaction is critical in many aspects of river, coastal and estuarine studies.

For my PhD project, hydrodynamic, sediment properties, bedform dimensions, and migrations and water properties are measured in different ways. During each cruise, we deploy the anonymous MARUM / COSYNA bottom lander SedOBS, equipped with different instruments, on the seabed.

I am working on developing codes for Acoustic Doppler Velocimeter (ADV) and Laser In Situ Scattering Transmissometry (LISST) devices, which are capable of measuring high frequency velocity vectors, suspended sediment concentrations and particle sizes. Using the velocity vectors, I quantify turbulence in two different time scales:

1. In integrated time scale, common turbulent statistics such as Reynolds stress and turbulent kinetic energy are calculated. These parameters are correlated with averaged suspended sediment concentration.

2. In process time scale , different types of turbulent events (outward interactions, ejections, inward interactions and sweeps) are detected. The evolution of these events over tidal cycle is evaluated by every single one of them. Finally, the turbulent events on the sediments are transported to the sediments in subaqueous flows.

Please have a look at Coastal Dynamic Group webpage to become familiar with our research group.

Amir­s­hahi, SM , Kw, E. and Win­ter, C. (2018) Near Bed Suspended Sediment Flux by Single Turbulent Events. Cont. Shelf Res. 152, 76-86. doi: 10.1016 / j.csr.2017.11.005

Amir­s­hahi, SM , Kwoll, E. and Win­ter, C. (2016) Cha­rac­te­ris­tics of in­stan­ta­neous tur­bu­lent events in sou­thern Ger­man Bight. Pro­cee­dings of Ri­ver Flow 2016, St. Lou­is, Mis­sou­ri, USA

Khan­pour, M., Zar­ra­ti, AR, Ko­lah­doo­zan, M., Shaki­ba­ei­nia, A. and Amir­s­hahi, SM (2016) Mesh-free SPH mo­de­ling of se­di­ment scou­ring and flus­hing. Com­put. Fluids 129, 67-78. doi: 10.1016 / j.com­pf­lu­id.2016.02.005

Amir­s­hahi, SM and Zar­ra­ti, AR (2013) Mo­de­ling Tur­bu­lence In­ten­si­ty in Phy­si­cal Mo­del. 9th In­ter­na­tio­nal Ri­ver En­gi­nee­ring Con­fe­rence, Ah­vaz, Iran (in Per­si­an)