/PROP/TYPE34 (SPH)

Block Format Keyword

/PROP/TYPE34 (SPH) - SPH Property Set

Description

Describes SPH property set.

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/PROP/TYPE34/prop_ID or /PROP/SPH/prop_ID
prop_title
mp		qa		qb				skew_ID
order	h		stab

Field	Contents	SI Unit Example
prop_ID	Property identifier (Integer, maximum 10 digits)
prop_title	Property title (Character, maximum 100 characters)
mp	Mass of the particles (Real)
qa	Quadratic bulk viscosity Default = 2.0 (Real)
qb	Linear bulk viscosity Default = 1.0 (Real)
	Conservative smoothing coefficient (Real)
skew_ID	Skew identifier to define the initial orthotropic directions in the case of skew_ID ≠ 0 (means property is orthotropic). (Integer)
order	SPH correction order Default = 0 (Integer) = -1: means no correction at all = 0: means order 0 correction = 1: means correction up to order 1 - not allowed for SPMD parallel version.
h	Smoothing length Default: see Comment 2 (Real)
stab	Coefficient for solving tensile instability Default = 0.0 (Real)

(Bird Strike)

#RADIOSS STARTER

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/PROP/TYPE34/3000001

BIRD_sphv1 (unit kg_mm_ms) data from Example 49 - Bird Strike on Windshield

# mp qa qb alpha_cs

1.725149E-4 2E-30 1E-30 0

# order h xi_stab

0 6.286 0

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#ENDDATA

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

1.	The kinetic energy absorbed by conservative smoothing of velocities is output as hourglass energy into TH files.

2.	Default value for smoothing length is set as:

which corresponds to the inter-particles distance assuming that the particles distribution is hexagonal compact.

3.	It is recommended to use a regular distribution of particles even when using SPH corrections. Concerning the smoothing length value to be given (refer to SPH Cells Distributions).

4.	If stab is not equal to zero, an artificial stress is added in order to solve the tensile instability, proposed by:

J.J. Monaghan, SPH without a Tensile Instability, Journal of Computational Physics, vol. 159, pp. 290-311, 2000

A value of stab = 0.3 is recommended.

5.	If the PID is used with Sol2SPH option, h must be input by you. The mass of the particle can be 0.0 (it is automatically calculated by RADIOSS), a good value of the smoothing length is:

Where, h is the smoothing length, l is the size of the brick elements, and Ndir is the number of particle per direction for each solid elements.