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CAE Simulation

Boundary Condition Standards: Environmental Physics Fidelity

In computational engineering, the accuracy of the result is directly proportional to the realism of its constraints. Edelweis enforces a strict Boundary Condition (BC) Standard to ensure virtual simulations mirror the physical world, eliminating "mathematical artifacts" and providing high-confidence data.

1. Structural Boundary Protocols (FEA)

We define the "Degree of Freedom" (DoF) for every interface to prevent artificial stiffening or unrealistic deformation:

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    Fixed & Pinned: Rigid fixity is reserved for supports stiffer than the component; Pinned supports allow rotation to avoid artificial moment stresses.
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    Elastic Support: Utilizing Spring Constants (k) to simulate the "give" of gaskets or foundations for realistic stress distribution.
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    Bolt Preload: Fasteners are never modeled as "bonded"; calculated clamping forces account for initial internal stress states.

2. Fluid & Thermal Boundary Protocols (CFD)

Inlet Physics
Prioritizing Mass Flow Inlets for compressible gases with standardized 5% turbulence intensity.
Outlet Logic
Defining pressure based on ambient environment to capture correct gradients.
Wall Functions
Incorporating physical roughness values to calculate skin friction and pressure drops accurately.

3. Thermal Interface Management

BC Type Implementation Engineering Purpose
Adiabatic Wall Zero heat flux. Simulating ideal thermal isolation.
Convective Film Defined by h-coefficient. Simulating cooling from ambient air/liquids.
Thermal Contact Contact Resistance (TCR). Accounting for microscopic air gaps between surfaces.
Radiation Sink Emissivity & View Factors. Critical for high-temp vacuum or solar loading.

4. Dynamic & Transient BCs

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    Pulsating Inlets: Sinusoidal functions to simulate piston pumps or cyclic combustion cycles.
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    Moving Reference Frames: Simulating fans and turbines without full sliding mesh, optimizing solve time.
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    Time-Step Sensitivity: Ensuring Delta-T is small enough to capture physics (Courant number < 1).

Technical Directives

Directive Protocol
Load Path Audit Every BC must be cross-verified against the project Safety Factors matrix.
Saint-Venant’s Check Point loads are prohibited; loads must be distributed via remote forces or pressure patches.
Gravity Alignment Gravity vectors must be strictly aligned with the Master Skeleton orientation.