0
TECHNICAL PAPERS

Prediction of Falling Cylinder Through Air-Water-Sediment Columns

[+] Author and Article Information
Peter C. Chu1

Naval Ocean Analysis and Prediction Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943chu@nps.navy.mil

Chenwu Fan

Naval Ocean Analysis and Prediction Laboratory, Department of Oceanography, Naval Postgraduate School, Monterey, CA 93943

1

To whom correspondence should be addressed.

J. Appl. Mech 73(2), 300-314 (Aug 04, 2005) (15 pages) doi:10.1115/1.2125975 History: Received March 02, 2004; Revised August 04, 2005

A falling rigid body through air, water, and sediment is investigated experimentally and theoretically. Two experiments were conducted to drop rigid cylinders with density ratio around 1.8 into shallow water (around 13 m deep) in the Monterey Bay (Exp-1) and into the Naval Postgraduate School’s swimming pool (Exp-2). During the experiments, we carefully observe cylinder track and burial depth while simultaneously taking gravity cores (in Exp-1). After analyzing the gravity cores, we obtain the bottom sediment density and shear strength profiles. The theoretical work includes the development of a 3D rigid body impact burial prediction model (IMPACT35) that contains three components: triple coordinate transform and hydrodynamics of a falling rigid object in a single medium (air, water, or sediment) and in multiple media (air-water and water-sediment interfaces). The model predicts the rigid body’s trajectory in the water column and burial depth and orientation in the sediment. The experimental data (burial depth, sediment density, and shear strength) show the capability of IMPACT35 in predicting the cylinder’s trajectory and orientation in a water column and burial depth and orientation in sediment.

Copyright © 2006 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Figure 14

Movement of cylinder 2 (L=12.10cm,ρ=1.67gcm−3) with χ=−1.00cm and drop angle 30 deg obtained from (a) experiment, (b) 3D IMPACT35 model, and (c) 2D Impact28 model

Grahic Jump Location
Figure 15

Comparison among observed and predicted burial depths

Grahic Jump Location
Figure 9

Internal components of the model cylinder

Grahic Jump Location
Figure 10

Exp-1 equipments

Grahic Jump Location
Figure 11

Top view of Exp-1

Grahic Jump Location
Figure 12

Mean sediment density ρs(z) and shear strength S(z) profiles in the Monterey Bay collected during the cylinder drop experiment on May 31, 2000

Grahic Jump Location
Figure 13

Movement of cylinder 1 (L=15.20cm,ρ=1.69gcm−3) with χ=0.74m and drop angle 45 deg obtained from (a) experiment, (b) 3D IMPACT35 model, and (c) 2D Impact28 model

Grahic Jump Location
Figure 1

M-coordinate with the COM as the origin X and (im,jm) as the two axes. Here, χ is the distance between the COV (B) and COM (X), (L,R) are the cylinder’s length and radius.

Grahic Jump Location
Figure 2

Three coordinate systems

Grahic Jump Location
Figure 3

Three patterns of cylinder penetration with the cross section being (a) a complete ellipse, (b) a cutoff ellipse with one side straight line, and (c) a cutoff ellipse with two side straight lines

Grahic Jump Location
Figure 4

Illustration of PCOV (B−), x1, and ξ− for the tail part [C(1),D(1)] for the case in Fig. 3

Grahic Jump Location
Figure 5

Geometry of the part D(1)

Grahic Jump Location
Figure 6

The impact (resistant) force exerted on the part of the object’s surface moving towards the sediment

Grahic Jump Location
Figure 7

Momentum and angular momentum balance for the cylinder’s penetration through the water-sediment interface

Grahic Jump Location
Figure 8

Procedure of the recursive model

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In