Workshop we are not there yet 2

Rheology as a survey tool: We are not there yet ! Stijn Claeys Thomas Van Hoestenberghe

Vessel Mud Contact “ Feeling the mud“ = Based on reaction forces of mud exerted on the vessel when trying to sail through it Direct contact Induced influence triggered by hydrodynamic activity (internal wave) Nautical bottom detection by density Density – related? - resistance “ Hard bottom” Top of sludge Nautical bottom

reaction forces Buoyancy Stickiness Rheology Deformation “ dull or sharp shape”: => different exerting forces A small point of contact, magnifying the force ! Knowing the shape parameters = knowing the applied force. Density difference; volume Shape parameter ,[object Object],[object Object],[object Object],[object Object],[object Object],Roughness; surface Dispersive adhesion properties of mud Other: Hydrodynamics during sailing (currents around the hull, propeller action etc…) Very complex => Nautica Bearing capacity

Sampling & laboratory Acoustical Measuring principles Mechanical Gamma Optical Field test = difficult => Tested in the (Mud) Sludge Test Tank Gas cleaner: odour Sludge selection reservoir Pump reservoir Hydro cyclone Bridge with mixing/jetting device Aeration Sampling and observation Measuring mud properties Laboratory protocol

Mechanical based instruments= “feeling the mud” towing Towed body vibrating Tuning fork ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Force needed to maintain the applied chosen vibration ( shear rate = vibrating frequency) The restriction of the method is bound to a good calibration => need to seek the correct position on the shear stress-shear rate rheogram Info on mud column Lateral 1 level info Mechanical interaction Type of instrument Towed body <= reaction forces => vessel

rotating decelerating rheometer free fall cone penetration test (FF CPT) (cable burial, deep sea trenching) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Info on mud column Info on mud column Mechanical based instruments = “feeling the mud” profiling tube Mechanical interaction Type of instrument Free fall body <= reaction forces => vessel Rheometer In-situ => rheometer laboratory

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Mechanical = destructive method : “disturbing the mud”

Tuning Towing ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Measuring device Vessel = Mechanical Mechanical Deceleration Different application scale Rotating Sampling & laboratory Acoustical Gamma Optical DIRECT LINK ? Yes , but not defined => physical model, mathematical model, CFD Research = Non-mechanical Translation into rheology (if possible) & Calibration DIRECT LINK ? Yes , but not defined => physical model, mathematical model, CFD Extra difficulty Level / possible? Non-DIRECT LINK Research Mainly based on density

Research (*) CFD Relate Vessel-Mud Labo-protocol Field-protocol Defining “the” rheology Parameters Mud research: Historical, recent and new Laboratory and Sludge Test Tank. “Micro scale” Nautical research: Historical, recent and new Physical and scale model, 3D simulation. “Macro scale” ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],In-situ measuring protocol “ Nautical bottom” ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Field Map the mud parameters

We are not there yet ! Rheology as a nautical survey tool Continuing using density (different type of instruments) combined with a safe keel-clearance ,[object Object],[object Object],[object Object],[object Object],[object Object],Paper available [email_address]

Towing or profiling Towing Profiling ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Before the high resolution vertical profiling, towing was preferable.

Workshop we are not there yet 2

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