For 2D components, if Uniform distribution is selected, enter the Number of particles per release N (dimensionless). The default is 1. The union of the selected edges is divided into N segments of approximately equal length, and a particle is placed in the middle of each segment.
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For 3D components, if Projected plane grid is selected, enter the Number of particles per release N (dimensionless). The default is 1. The particles are distributed on a plane grid in planes that are approximately tangential to the selected boundaries.
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For Expression enter expressions for the Initial particle velocity v0 (SI unit: m/s) based on space dimension. Select the Specify tangential and normal vector components check box to enter expressions for the initial velocity in terms of the tangential and normal directions at the surface.
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When using The Particle Tracing for Fluid Flow Interface, enter a value or expression for the Velocity field u. If another physics interface that computes the velocity field is present, then this interface can be selected from the list.
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For Kinetic energy and direction enter the Initial kinetic energy E0 (SI unit: J). The default is 1 keV. Then enter coordinates for the Initial particle direction L0 (dimensionless) based on space dimension. It is not necessary to normalize the components of the initial direction vector because this is done automatically when computing the initial velocity. Select the Specify tangential and normal vector components check box to enter expressions for the initial direction in terms of the tangential and normal directions at the surface.
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The option Kinetic energy and direction is not supported for The Particle Tracing for Fluid Flow Interface.
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For Constant speed, hemispherical enter a Speed v0 (SI unit: m/s), the Number of particles in velocity space Nvel (dimensionless), and the Hemisphere axis r. Select the Specify tangential and normal vector components check box to enter expressions for the hemisphere axis in terms of the tangential and normal directions at the surface.
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For Constant speed, cone enter a Speed v0 (SI unit: m/s), the Number of particles in velocity space Nvel (dimensionless), the Cone axis r, and the Cone angle α (SI unit: rad). Select the Specify tangential and normal vector components check box to enter expressions for the cone axis in terms of the tangential and normal directions at the surface.
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The Constant speed, Lambertian option is only available in 3D. Enter a Speed v0 (SI unit: m/s), the Number of particles in velocity space Nvel (dimensionless), and the Hemisphere axis r. The velocity distribution is a hemisphere in which the distribution of polar angles follows the cosine law, similar to the Diffuse scattering option for the Wall feature. Select the Specify tangential and normal vector components check box to enter expressions for the hemisphere axis in terms of the tangential and normal directions at the surface.
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For Thermal, enter a value or expression for the Temperature T of the boundary (SI unit: K). The default is 293.15 K. If the temperature is computed by another physics interface in the model then it can be selected from the list. The Thermal option samples the initial particle velocity from a distribution in the same manner as the Thermal Re-Emission boundary condition. For more details see About the Boundary Conditions for the Particle Tracing Interfaces in the Theory for the Mathematical Particle Tracing Interface section.
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When the Specify tangential and normal velocity components or Specify tangential and normal vector components check box is selected, arrows indicating the normal direction on the selected boundaries will appear in the Graphics window.
Note that the normal direction may be opposite the built-in variable for the boundary normal (for example, nx, ny, and nz) to ensure that a positive value causes particles to be released into the simulation domain. This often occurs when the Inlet is applied to exterior boundaries.
When the normal direction used by the Inlet feature is opposite the normal vector defined by the geometry, the tangential directions are similarly inverted to ensure that the boundary coordinate system is right-handed.
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For example, if Constant speed, hemispherical is selected from the Initial velocity list, the Allow nonuniform speeds in distribution check box is selected, and the expression for the initial speed is 2[m/s]*(random(pt.pidx)+0.5), then particles will be released with directions sampled from an isotropic hemisphere and with speeds sampled pseudorandomly between 0 and 2 m/s.
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