NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Fluid-structural dynamics of ground-based and microgravity caloric testsMicrogravity caloric tests aboard the 1983 SpaceLab1 mission produced nystagmus results with an intensity comparable to those elicited during post- and pre- flight tests, thus contradicting the basic premise of Barany's convection hypothesis for caloric stimulation. In this work, we present a dynamic fluid structural analysis of the caloric stimulation of the lateral semicircular canal based on two simultaneous driving forces for the endolymphatic flow: natural convection driven by the temperature-dependent density variation in the bulk fluid and expansive convection caused by direct volumetric displacement of the endolymph during the thermal irrigation. Direct numerical simulations indicate that on earth, the natural convection mechanism is dominant. But in the microgravity environment of orbiting spacecraft, where buoyancy effects are mitigated, expansive convection becomes the sole mechanism for producing cupular displacement. A series of transient 1 g and microgravity case studies are presented to delineate the differences between the dynamics of the 1 g and microgravity endolymphatic flows. The impact of these different flow dynamics on the endolymph-cupula fluid-structural interactions is also analyzed based on the time evolutions of cupular displacement and velocity and the transcupular pressure differences.
Document ID
20050218771
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kassemi, M.
(NASA Glenn Research Center Cleveland, OH United States)
Oas, J. G.
Deserranno, Dimitri
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Publication Information
Publication: Journal of vestibular research : equilibrium & orientation
Volume: 15
Issue: 2
ISSN: 0957-4271
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available