[{"data":1,"prerenderedAt":50},["ShallowReactive",2],{"$fx2kcu3puk8yw":3},{"slug":4,"publishedAt":5,"category":6,"title":7,"summary":8,"image":9,"imageAlt":14,"readingMinutes":15,"serviceId":16,"keywords":17,"imageCaption":21,"sections":22,"sources":43},"verification-and-validation","2026-10-06","methods","Verification and validation: two different questions","A converged CFD solution is a starting point. Numerical checks and comparison with physical evidence answer different questions about a model.",{"src":10,"thumbnail":11,"width":12,"height":13},"\u002Fassets\u002Fcfd-cases\u002Fvalidation\u002Fimages\u002F03.webp","\u002Fbrand\u002Fstudies\u002Fvalidation.svg",1672,941,"DEEB-FLOW concept illustration of a heat-transfer experiment and numerical comparison",2,"review",[18,19,20],"CFD verification","CFD validation","mesh sensitivity","Brand illustration only. The plotted curves are illustrative, not a measured validation result.",[23,28,33,38],{"id":24,"title":25,"paragraphs":26},"numerics","Verification examines the numerical calculation",[27],"Verification asks whether the numerical solution represents the mathematical model with sufficient accuracy for the intended use. Residual behaviour, conservation balances and the stability of engineering outputs are relevant checks. A small residual alone does not establish that pressure loss, heat transfer or another decision variable is insensitive to numerical choices.",{"id":29,"title":30,"paragraphs":31},"mesh","Mesh sensitivity is about quantities that matter",[32],"Refine the mesh systematically and compare the same engineering quantities under consistent physical conditions. Watch where refinement changes the answer, particularly near walls, jets, interfaces and steep gradients. Where appropriate, a grid-convergence study can help estimate discretisation uncertainty. Agreement between two meshes is useful evidence, but is not experimental validation.",{"id":34,"title":35,"paragraphs":36},"physics","Validation compares the model with physical evidence",[37],"Validation considers how well the chosen physical model describes the real system for its intended use. Compare with relevant measurements under matching operating conditions, with measurement uncertainty in view. Matching a single measured quantity does not prove that every internal field is correct or that the model is reliable outside the conditions examined.",{"id":39,"title":40,"paragraphs":41},"decision","Report the limits alongside the conclusion",[42],"Record assumptions, boundary conditions, numerical checks and the conditions covered by the evidence. Separate numerical uncertainty from uncertain inputs and modelling limitations. If relevant measurements are unavailable, say so and define what a future test should measure. The useful outcome is a decision supported by stated evidence, not an unqualified claim that the model is validated.",[44,47],{"label":45,"href":46},"NASA \u002F NPARC: verification and validation overview","https:\u002F\u002Fwww.grc.nasa.gov\u002Fwww\u002Fwind\u002Fvalid\u002Ftutorial\u002Foverview.html",{"label":48,"href":49},"NASA \u002F NPARC: spatial grid convergence","https:\u002F\u002Fwww.grc.nasa.gov\u002Fwww\u002Fwind\u002Fvalid\u002Ftutorial\u002Fspatconv.html",1791759706631]