A runtime strategy where distinct simulation codes or solvers execute concurrently (possibly on different processes or hardware) and exchange data at predefined synchronization points under a coordination protocol or master algorithm.

Principle

Maintain temporal and data consistency across heterogeneous simulators by defining synchronization schedules, exchange variables and interpolation/hold strategies so that concurrent execution produces a coherent coupled trajectory.

Demonstration

A vehicle simulation runs a detailed tire dynamics model, an engine control model, and a rigid‑body vehicle dynamics solver as separate processes; at each synchronization instant the components exchange forces, torques and state estimates to evolve the integrated simulation in real time or accelerated time.

Misapplication

Forcing co‑simulation with coarse synchronization intervals or without consistent time interpolation between models that have disparate time scales can lead to aliasing, drift, or loss of stability in the coupled result.

Consequence

Enables interoperability of heterogeneous tools, hardware‑in‑the‑loop setups, and distributed execution while preserving component fidelity; it introduces complexities in synchronization, latency, and reproducibility that must be managed.

Reversal

Tightly integrated single‑process simulation where all model equations are advanced by a common integrator and there is no runtime data exchange protocol between independent executables.

Boundary

Refers specifically to runtime concurrent execution and data exchange; it excludes offline data transfer, purely sequential co‑execution without synchronization, or purely analytical coupling of models.

Semantic Tension

Co‑simulation overlaps with partitioned coupling but emphasizes runtime concurrency, heterogeneity of implementations and orchestration protocols; nearby meanings may conflate it with any modular coupling regardless of execution timing.

Synthesis

Co‑simulation is the coordinated, concurrent execution of heterogeneous simulators with controlled data exchange and synchronization, trading engineering interoperability and component fidelity against added runtime coordination complexity.