Modal Analysis of Water Distribution Systems (EWCM)
Part of my PhD research at the University of Adelaide. We adapt modal analysis (eigen-modes, damping, spatial mode shapes) to water networks using the Elastic Water Column Model (EWCM). This gives utilities a fast, state-space view of where resonance amplifies transients and how to mitigate them.
What problem does this solve?
Transients can quietly build at specific locations and frequencies. Classical frequency-domain tools show what frequencies matter; our method also shows where in the network each mode lives — so you can prioritise mitigation and monitoring.
Outcomes for operators
- Identify vulnerable nodes/links using PF maps.
- Test “what-if” changes (PRV ramps, pump trips) before you implement.
- Build reduced-order, control-ready models from dominant modes.
Representation for a small network
How it works (in brief)
Linearize EWCM
Steady operating point → state-space model of WDSs.
Eigen-analysis
Eigenvalues → frequencies & damping; eigenvectors → mode shapes.
Participation Factors
PF quantifies each node/pipe’s contribution to each mode → spatial risk.
Show technical notes
- Validated vs. admittance-matrix poles in the Laplace domain.
- PFs derive from left/right eigenvectors; sums over states/modes = 1.
- Sparse matrices and per-pipe reaches keep it scalable.