Identification

Title

The application of potential flow theory to the rotational dynamics of spheroids, disks, and cylinders

Abstract

The purpose of this work is to obtain estimates of the torque exerted by a fluid on a translating object and also of the frequency of the rotational oscillation that results from this torque. The approach employed is to assume spheroidal geometry for the translating objects and to assume that the flow around these spheroids may be approximated by potential flow. Potential flow torques and oscillation frequencies for prolate and oblate spheroids are computed and compared to measured values for spheroids, disks, and cylinders found in the literature. The results of this comparison lie in four areas. First, it is found that potential flow torques are consistently larger than measured torques, and the reason for this is discussed. Second, and as a corollary, it is found that potential flow oscillation frequencies are also greater than measured frequencies. Third, it is suggested that the observed oscillation frequencies are determined by the nearly potential flow on the objects' upstream sides rather than by the natural frequency of vortex shedding, as suggested by the remarks of some authors. Fourth, the tumbling, or autorotation, that is observed to occur for some solids while translating through fluids is examined in light of these results. In particular the possibility is considered that the tumbling results from a resonance between periodic conditions in the wake of an object and a natural frequency of oscillation that is characteristic of the object and the nearly potential flow on its upstream side.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d77d2wrt

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

1985-08-20T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact