### ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

## 1aSC29. Vocal tract simulations based on fluid dynamic analysis.

**G. Richard
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M. Liu
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D. Sinder
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H. Duncan
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Q. Lin
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J. Flanagan
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**
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*Rutgers Univ.---CAIP Ctr., Piscataway, NJ 08855-1390
*

*
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**S. Levinson
**

**
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*AT&T Bell Labs., Murray Hill, NJ 07974
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*
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**D. Davis
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S. Simon
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**
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*General Dynamics, Groton, CT 06340
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*
*
An alternate approach to speech synthesis based on direct numerical
solution of Navier--Stokes (NS) and Reynolds-averaged-Navier--Stokes (RANS)
equations is described. Unlike the traditional methods based on linear acoustic
theory, the NS and RANS formulations are not limited by the assumptions of
linearity, negligible viscous effects, and plane-wave propagation. The expected
results are high-quality synthesis and a new parametrization of speech for
applications in automatic recognition and low bit-rate coding resulting from a
parsimonious modeling of articulatory shapes and dynamics. In the present
formulation, the Navier--Stokes equations are discretized and solved using a
finite-difference method. An initial application involves a 2-D simulation of
flow through ideal channels (straight, dilating, and constricting tubes) with
rigid walls and constant boundary conditions (constant flow velocity at inlet,
zero pressure at outlet). As expected for these simple geometries, the
resonance frequencies correspond to those predicted by linear acoustics. In a
second application, the formulation is applied to the geometry of the three
cardinal vowels. For these cases, periodic inflow boundary conditions are also
used (a train of short pulses to represent vocal cord excitation). Synthetic
speech sounds of encouraging quality are obtained for the three vowels.
[Research supported by NSF/ARPA IRI-9314946 and ARPA DAST 63-93-C-0064.]