Residuals explode or the solver stops
Review units, boundaries, initialization, mesh quality, source terms, properties and physics before applying numerical damping.
CFD TROUBLESHOOTING & INDEPENDENT MODEL REVIEW
When the simulation runs—but you do not trust what it is telling you.
Abecator provides focused CFD troubleshooting and independent technical review for unstable cases, slow convergence, mesh problems, y+ mismatch, outlet issues, conservation errors and results that are numerically converged but physically questionable.
COMMON SYMPTOMS
Separate root cause from solver symptoms.
Changing under-relaxation, timestep or solver controls can hide a setup problem. The review starts by classifying whether the dominant issue is physical, geometric, mesh-related, numerical or interpretive.
Residuals flatten but monitors drift
Determine whether the problem is genuinely steady, whether monitors are sufficient and whether oscillation is physical or numerical.
Reverse flow or outlet sensitivity
Assess outlet location, recirculation, pressure-boundary consistency and whether backflow is physical or a domain artifact.
Near-wall results miss the intended strategy
Review prism layers, first-cell height, solved y+, growth, total thickness, local collapse and wall-treatment consistency.
Mass or energy does not close
Track fluxes, sources, interfaces, sign conventions and reporting definitions before trusting derived performance metrics.
The result looks wrong despite convergence
Challenge pressure, temperature, velocity, heat flux and force magnitudes using scaling, limits and independent engineering checks.
REVIEW SEQUENCE
A controlled diagnostic process instead of random solver tuning.
The first objective is to find the smallest set of checks that can falsify the most likely failure modes.
01
Define expected physics
What should mass flow, pressure, temperature, forces or heat balance roughly look like before CFD detail is considered?
02
Check model consistency
Units, properties, domains, boundaries, interfaces, reference frames and source terms are reviewed as a connected system.
03
Check mesh & numerics
Quality, prism layers, local refinement, timestep, discretization and solver controls are evaluated against the physics.
04
Verify the result
Conservation, sensitivity, monitor behaviour, extrema and independent scaling determine whether the result is credible.
WHAT A REVIEW CAN COVER
From a fast second opinion to a structured technical audit.
The review scope can be limited to a single symptom or expanded to the full model methodology.
A✓
Geometry & domain logic
Fluid regions, topology, interfaces, periodicity, volume extraction and whether the domain matches the intended physics.
B✓
Mesh & near-wall strategy
Surface/volume resolution, prism layers, local controls, cell quality, y+ and mesh-sensitivity logic.
C✓
Physics & boundary conditions
Turbulence, thermal/multiphase choices, material data, inlet/outlet definitions, interfaces and source terms.
D✓
Numerics, monitors & reporting
Solver strategy, timestep, residual interpretation, engineering monitors, conservation and post-processing definitions.
POSSIBLE DELIVERABLES
A prioritized technical conclusion—not a list of every setting.
The objective is to identify what most threatens the engineering conclusion and what should be changed or tested next.
Risk-ranked review notes
Major concerns, likely root causes, evidence and recommended corrective actions in priority order.
Troubleshooting plan
A controlled set of tests to distinguish competing causes without rebuilding the whole case blindly.
Verification checklist
Conservation, sensitivity, monitor and plausibility checks required before the model should support a decision.
Corrected methodology guidance
Where scope requires it, recommended updates to mesh, physics, boundaries, solver setup or reporting logic.
RELATED ABECATOR RESOURCES
Use the free diagnostics first—or bring the difficult case directly.
The public tools and Technical Cases show the diagnostic approach used before consultancy becomes necessary.
CFD Troubleshooter → Simulation Diverges → Reverse Flow at Outlet → y+ Misses Target →
NEED A SECOND ENGINEERING OPINION?
Send the symptom, what has already been checked and what decision depends on the CFD.
Use the project inquiry to build a concise technical brief. Start with non-confidential context; detailed file exchange can be agreed later if needed.
SELF-DIAGNOSE FIRST
Use the public diagnostic resources before paying for model-specific review.
The tools and Technical Cases are designed to solve common CFD problems independently. Consulting becomes useful when the diagnosis depends on your actual geometry, assumptions, mesh or evidence.