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The Vertical Movement Option frame provides the user the option of fixing the temporal position of the particles at their initial seeding depths. If this is unchecked the particles will drift vertically as Fully 3D Lagrangian Neutrally Buoyant Particles. A sub-option is Adjust Particle Depth. The This is the default option and adjusts particle depth with change in water depth. In some cases the user may wish to disallow this so that particles are not adjusted by change in water depth. The , and so can turn off this adjustment by unchecking this box. If the Adjust Particle Depth is selected, the amount of adjustment in the vertical direction depends on the ratio of particle depth and water depth when the particle is on the water surface. The formula of the vertical adjustment is:
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In which dzp is the adjustment of vertical particle depth, pdep is particle depth, wdep is water depth and dH the discrepancy of water depth of the current and previous timestimestep.
Within the Initial Particle Vertical Position Input Option the user may specify whether the vertical positions provided are elevations or depths.
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