Turbulent Suspension of Sediments in Tidal Environment
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.
|03.2014 - present||PhD candidate, MARUM, University of Bremen, Germany.|
|09.2010 - 02.2013||M.Sc., Hydraulic Structures, Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.|
Thesis title: Experimental Study on Effect of Turbulence Intensity on Riprap Stability
|09.2005 - 04.2010||B.Sc., Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran.|
|09.2001 - 06.2005||Diploma in Mathematics and Physics, Tehran, Iran.|
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)