Introduction to Simulation Modes
R-THYM provides two primary simulation environments designed for different phases of infrastructure planning, design, and operations. Because hydraulic systems behave differently depending on the time scale being analyzed, we have separated our solver into two distinct modes: Extended Period Simulation (EPS) and Dynamic Transient Mode (MOC).
Extended Period Simulation (EPS)
EPS is your operational planning tool. It is designed to model the behavior of your system over long durations that run over hours or days.
Use EPS when your goal is to:
- Evaluate diurnal demand patterns and reservoir filling cycles.
- Analyze daily energy expenditure, including peak-pricing and renewable energy utilization.
- Verify that your system has adequate capacity to meet consumer demands under normal operating conditions.
- Test control logic, such as PID settings or automated pump scheduling, to see how they affect system efficiency over time.
In EPS mode, the engine treats water as an incompressible fluid and focuses on steady-state hydraulic conditions. It is the best way to understand the macro-level movement of water and the financial costs of your operational decisions.
Dynamic Transient Mode (MOC)
MOC (Method of Characteristics) is your system protection tool. It is designed to model rapid physical changes that occur over seconds or fractions of a second.
Use MOC when your goal is to:
- Analyze water hammer events, such as pump trips, grid failures, or rapid valve closures.
- Design and verify surge protection measures like surge tanks, pressure relief valves, or air chambers.
- Ensure that system pressures remain within safe limits during emergency shutdown scenarios.
In MOC mode, the engine treats water as a compressible fluid and accounts for pipe elasticity. It tracks the propagation, reflection, and damping of high-speed pressure shockwaves.
Choosing Your Mode
To choose the right environment for your current task, consider the time scale and the physical event you are studying.
| Feature | EPS (Extended Period) | MOC (Dynamic Transient) |
|---|---|---|
| Time Scale | Minutes, Hours, Days | Milliseconds, Seconds |
| Primary Focus | Operational Planning & Energy | Safety & Surge Protection |
| Physics | Steady-State / Incompressible | Wave Propagation / Compressible |
| Key Output | Daily Trends, Tank Levels, Costs | Pressure Spikes, Wave Decay |
Integrated Workflow
These modes are not isolated. R-THYM is designed to allow you to transition between them in your workflow. Often, you will use EPS to establish a "steady-state" snapshot of your system to determine the flow rates and pressures at a specific moment in time. Once that is established, you can then trigger the MOC engine from that exact state to see how the system reacts to a sudden, critical event.
The following chapters detail how to configure and run simulations in both EPS and Dynamic Transient modes.