WP F/L A mechanical design for a detection unit for a deep- sea neutrino telescope VLVnT11 - Edward Berbee - Nikhef

WP F/L First concept DOMBAR Fits in ISO container 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L 13/10/ VLVnT11 - Edward Berbee - Nikhef First design 6 m Mechanical Cable Connection Rope & Cable Storage Rope Storage Bar Frame Optical Module Mechanical Interface 2 DOM + 1 BAR = 1 DOMBAR 20 DOMBARS = DOMTOWER

WP F/L Floating problem due to flatness Because of the “flat” top-view the floor tends to float in horizontal direction. 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L “turning flaps” “hosted hood” “tuning drum” Other design ideas; abandoned 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Data VEOC Mechanical cable (Dyneema rope) VEOC management 2 double reels for unwinding the ropes 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Some design considerations; -2 ropes wound around braked cable reels (and so under tension) to perform the unfurling controlled. -Buoyancy on each floor, above the center of gravity to insure horizontal unfurling of the floors. -Keep the unfurling speed low for better control (but not to low for drifting away due to current). -Keep the DU-package compact for easy handling and transportation. -The rope- and cable unfurling as well as all other items should not happen uncontrolled (without tension) at any moment. 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Slightly rotated bar structures for narrow stacking - complicated cable and rope management! 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Unfurling method -In all methods; tension in ropes absolutely necessary. Unwinding synchronized necessary? All in once, then from the bottom off the package. -Very high unfurling speed at the beginning. One by one, from the bottom up, -Unfurling speed more continuous. Buoyancy on each storey. No; -Less need for mechanical construction to separate one by one. Yes; - Mechanical construction to separate one by one absolutely necessary. Buoyancy on each floor. Yes; -Less need for mechanical construction to separate one by one. No; - Mechanical construction to separate one by one absolutely necessary. DOMBAR unfurling constrains; choice made 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Possible design Package; L x W x H 5800 x 2380 x 2050 mm Fits a “pallet wide” or “flat rack” container Floors clamped on vertical tubes, pulled off during unfurling, all under discussion. “flat rack” container 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Storey with yellow vertical optical cables (VEOC) and two double cable reels at the end (internally braked) Storey buoyancy, syntactic foam; approx. 450 N - 0,1M 3 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Verifying stable dynamic behavior 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L -20 bar structures. -Top buoy. -3 distance frames. -Baseframe with clamping tubes. -2 concrete “Stelcon” plates. -2 separator racks. 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Possible unfurling -Buoy is released. -Buoy pulls of first storey. -Buoy and first storey will pull off the second storey etc. -Released storey will make an approximately 45 degree turn while floating up. -Tensioned ropes, pull tension approximately 100 N each rope for better control during unfurling. -Each storey clamped with spring tensioned clamp on 5 vertical tubes, friction on these tubes approx. 500 N. 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Some details One of the two rollers from the bottom storey to connect to the base frame. Hinged support plates for stabilizing the end of bar structures. The three lower storeys are without optical modules. 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L 13/10/ VLVnT11 - Edward Berbee - Nikhef Distance frames, the lower one with running wheels For rotating of the DU. Concrete deadweight, (or steel) captured in aluminum profile. Lower active Bar Scaled picture Lower part of the DU Not scaled picture

WP F/L 13/10/ VLVnT11 - Edward Berbee - Nikhef Unfurling of a DU scale model from the seabed up

1:50 model area Real scale area 13/10/ VLVnT11 - Edward Berbee - Nikhef

13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Drag coefficients of importance for the DU For spheres the drag coefficient Cd= 0.5, For the Dom we take (some extra for the interface); In both horizontal and vertical directionCd = 0.7 Drag of the cables and ropes;Cd = 1.2 Drag coefficient for the aluminum tubes, circular rod, In both horizontal and vertical direction Cd = 1.2 Storey buoyancy; estimated for flow from the top; Cd = 0.9 estimated for flow from the side; Cd = 0.5 Top-buoy; estimated for flow from the top; Cd = 0.8 Estimated for flow from the side; Cd = /10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Hydro dynamic behavior Characteristics used: Rope OD (4x) 4 mm VEOC OD (2x)6.35 mm Top buoyancy1000 N Bar buoyancy450 N Total buoyancy10000 N Anchor3670 kg (concrete, weight in air) Anchor2450 kg (steel weight in air) Total transport weight7420 / 6200 kg Total weight in sea1120 kg Calculated drift165 v = 0.30 m/s  h = 30 cm/s  13/10/ VLVnT11 - Edward Berbee - Nikhef Used formula; Where: rho = the density of seawater = 1028 kg/m 3 v = the speed in m/s C d = the drag coefficient (dimensionless) A = surface area in m 2

WP F/L Influences on the amount of drag Rope OD (4x) 5 mm (instead of 4 mm) Drift179 v = 0.30 m/s VEOC OD (2x)10 mm (instead of 6.35 mm) Drift190 v = 0.30 m/s Some examples compared to the situation of the previous slide (drift 165 m); Top buoyancy7000 N (instead of 1000N) Bar buoyancy150 N (instead of 500N) Total buoyancy10000 N (still) Drift130 v = 0.30 m/s 13/10/ VLVnT11 - Edward Berbee - Nikhef

WP F/L Hydro dynamic behavior In vertical direction (during unfurling) (450 N local buoyancy) Calculated speed of 1000 N top-buoy at start;1.46 m/s Calculated speed first storey with top-buoy;1.13 m/s Calculated speed first two floors with top-buoy;1.03 m/s Calculated speed at the last floor;0.85 m/s 13/10/ VLVnT11 - Edward Berbee - Nikhef In vertical direction with a top buoy of 7000 N instead of 1000 N; (150 N local buoyancy) Calculated (vertical) speed top-buoy at start;2.48 m/s Calculated speed first storey with top-buoy;2.04 m/s Calculated speed first two floors with top-buoy;1.79 m/s Calculated speed at the last floor;0.89 m/s

WP F/L 13/10/ VLVnT11 - Edward Berbee - Nikhef Verifying vertical drag calculation on scale-model Calculated; 0,060m/s at 0,001 N buoyancy measured speed 0,065 m/s

WP F/L Summary; Calculation for the deviation of the top relative to the bottom at 0.30 m/s current; (possible to improve by a bigger top-buoy) 165 m Calculated speed of 1000 N top-buoy at start;1.46 m/s Calculated speed first storey with top-buoy;1.13 m/s Calculated speed at the last floor;0.85 m/s 13/10/ VLVnT11 - Edward Berbee - Nikhef