Skip to Content

5512 Pure Sway

Experiment

Forces and moment and phase-averaged Tomographic PIV (TPIV) local flow measurements are performed in a 3 m ´ 3 m ´ 100 m towing tank for a 3.048-m long geometrically similar model of surface combatant 5415 in pure sway maneuver.  Test conditions are for maximum drift angle  = 10° and Froude number Fr = 0.28.  The TPIV enables fully volumetric flow measurements and the use of -criteria enables vortex volume visualization and core analysis.  The objective of the experiment is to extend the knowledge for the static condition vortex separation onset and progression to unsteady dynamic conditions, including integrated CFD.  Test conditions meet the IITC criteria for sway frequency and restricted water restrictions.  Both the present and previous uncertainty assessment (UA) for forces and moment show acceptable values.  The uncertainty estimates for TPIV is done by using a practical approach and the results are comparable with the earlier UA using a conventional approach.  Integrated CFD simulations are used to identify flow vortices.  The comparison with the previous TPIV results for static maneuver conditions show improvements for the present TPIV using a more advanced algorithm.  The pure sway measurements at phases corresponding to straight-ahead and  = 10° show similarities and differences with the static maneuver measurements, whereas at intermediate phases substantial vortex interactions and unsteady separation onset and progression is shown.  The vortex core analysis shows similarities and differences in the core strength and trajectory with the static drift and dynamic pure yaw maneuvers.  The present experiment is ongoing and the initial measurement results are presented herein.

Data, Equipment, and Conditions

Data Equipment Fr Max. drift angle, bmax (°)
Flow field TPIV 0.28 2, 4, 10
Forces and moment Load cell 0.28 10

Sample Image

The following image shows a graphical rendering of the experimental setup showing the PMM carriage, model 5512, and the TPIV arrangement in the IIHR towing tank.This image shows a graphical rendering of the experimental setup showing the PMM carriage, model 5512, and the TPIV arrangement in the IIHR towing tank.The following images show the allocation of TPIV overlapping zones (the green boxes) at each measurement station (left) and a zoom-in view of station x = 0.2 in the yz-plane with showing the VW-streamlines (right).

These images show the allocation of TPIV overlapping zones (the green boxes) at each measurement station (left) and a zoom-in view of station x = 0.2 in the yz-plane with showing the VW-streamlines (right).Sample Data

The following images show planar views of the phase-averaged axial velocity (top left), turbulent kinetic energy (top right), axial vorticity (bottom left) measured at station x = 0.12 and the zoomed-in view of the volumetric iso-Q surfaces of the vortices.

These following images show planar views of the phase-averaged axial velocity (top left), turbulent kinetic energy (top right), axial vorticity (bottom left) measured at station x = 0.12 and the zoomed-in view of the volumetric iso-Q surfaces of the vortices.Get Data: 5415 Pure Sway Data

References

Yoon, H. and Stern, F., “Phase-averaged Tomographic PIV Measurements for Surface Combatant 5415 in Pure Sway Maneuver: Experimental Setup, UA, and Preliminary Results,” the 30th American Towing Tank Conference, West Bethesda, Maryland, October 2017.

 

Last modified on December 4th, 2017
Posted on November 15th, 2017