direct numerical simulation

Equations and regime

Record the instantaneous equations, material assumptions, forcing and nondimensional parameters with their conventions.

1. Which governing equations and constitutive assumptions define the flow, and which physical processes are omitted? definition
2. How are Reynolds number and any additional controlling parameters defined and measured for this case? measurement

Closure and label

Record the basis of the DNS designation, including turbulence closures, filters and any narrower scope of direct resolution.

1. Which turbulent motions are claimed to be resolved, and does any closure or numerical mechanism stand in for unresolved turbulence? boundary
2. Which publication or run documentation supports the DNS designation and states its limitations? provenance
3. For coupled scalar, reacting or multiphase physics, which processes are resolved directly and which remain modelled? boundary

Local resolution evidence

Record mesh or spectral resolution, its spatial variation and the diagnostics used to justify adequacy.

1. Which small-scale criteria apply to this flow, and how do local grid spacings or spectral cutoffs compare with them? measurement
2. Where do walls, intermittency or coupled transport introduce resolution demands that a domain-average criterion could conceal? boundary
3. Which refinement comparisons or spectral diagnostics support resolution of the observables being reported? provenance

Temporal and domain adequacy

Record time-step evidence, domain dimensions and boundary sensitivity separately from solver stability.

1. What time-step refinement evidence demonstrates accuracy for the fastest relevant dynamics and target observables? measurement
2. How do domain-size checks, correlations or boundary-sensitivity studies establish that important structures are accommodated? measurement
3. Which time-step, domain or boundary changes should be tested before accepting the DNS claim? action

Numerical error budget

Record spatial and temporal schemes, solver tolerances, applicable aliasing control and numerical contributions to flow budgets.

1. Which discretisations, tolerances, filters and aliasing controls were used, and how could they affect small-scale motion? definition
2. What applicable conservation, constraint or energy-budget checks quantify residual numerical error? measurement
3. How is artificial dissipation distinguished from the physical dissipation represented by the governing equations? measurement

Reproducible flow realisation

Record the software version, inputs, initialisation, forcing, restarts and verification evidence needed to reconstruct the calculation.

1. Which versioned code, configuration, initial conditions and forcing records identify the executed run? provenance
2. What verification cases or convergence results support the solver for the equations and boundary conditions used here? provenance
3. What must be preserved to reproduce the setup and statistically comparable results despite chaotic trajectory divergence? action

Observable-specific sampling

Record how statistics are formed and whether their temporal, spatial or ensemble support is adequate.

1. Which transient intervals are excluded, and what supports stationarity or the chosen treatment of a nonstationary flow? measurement
2. How are correlations, averaging assumptions and effective sample counts reflected in uncertainty for each target statistic? measurement
3. Does the saved field resolution and output cadence support the proposed spectra, gradients or event analysis? action

Supported inference

Record reference comparisons, mismatched conditions and limits on treating DNS outputs as evidence for other regimes.

1. Which experimental or reference datasets provide relevant comparisons, and how closely do their parameters and boundary conditions match? provenance
2. Which conclusions are confined to this Reynolds number, geometry, forcing and physical formulation? boundary
3. What additional checks or simulations are required before using these outputs to assess a closure model or generalise a physical claim? action

Check these first

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these check these first hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance

Kinds and varieties

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these kinds and varieties hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance

Real-world use

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these real-world use hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance

Typical measurements

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these typical measurements hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance

Failure modes and hazards

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these failure modes and hazards hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of direct numerical simulation this model covers, and on what evidence? provenance