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Internal Aerodynamics

In flu­id me­chan­ics, an in­ter­nal flow is a flow for which the flu­id is con­fined by a sur­face. Hence the bound­ary lay­er is un­able to de­vel­op with­out even­tu­al­ly be­ing con­strained. The in­ter­nal flow con­fig­u­ra­tion rep­re­sents a con­ve­nient geom­e­try for heat­ing and cool­ing flu­ids used in chem­i­cal pro­cess­ing, en­vi­ron­men­tal con­trol, and en­er­gy con­ver­sion tech­nolo­gies. Ap­pli­ca­tions there­fore in­clude flows in pipes, ducts, air con­ducts, cav­i­ties, jet en­gines or wind tun­nels.

 

The Poiseuille flow is a clas­sic and sim­ple prob­lem in vis­cous, lam­i­nar flow in­volv­ing the steady-state ve­loc­i­ty for a flu­id mov­ing lat­er­al­ly be­tween two plates whose length is much greater than the dis­tance sep­a­rat­ing them (Read more).

The cir­cu­lar Cou­ette flow con­sists of a vis­cous flu­id con­fined in the gap be­tween two ro­tat­ing cylin­ders. The ro­tat­ing cylin­ders brings the flu­id in mo­tion and the flow is con­sid­ered sta­ble for low an­gu­lar ve­loc­i­ties (Read more).

The back­ward fac­ing step is a chal­leng­ing nu­mer­i­cal prob­lem based on a sim­ple geom­e­try but re­tain­ing rich flow physics. It con­sists of a duct flow with the chan­nel sud­den­ly ex­pand­ing and cre­at­ing one or sev­er­al re­cir­cu­la­tion zones on the up­per and low­er parts of the chan­nels de­pend­ing on the Reynolds num­ber (Read more).

The dri­ven cav­i­ty prob­lem has long been used as a bench­mark­ing test case for in­com­press­ible CFD solvers.The stan­dard case is a flu­id con­tained in a square do­main with three sta­tion­ary sides and one mov­ing side (with ve­loc­i­ty tan­gent to the side). De­pend­ing on the Reynolds num­ber, dif­fer­ent vor­tex­es can ap­pear at var­i­ous lo­ca­tions (Read more).

The flow of Non-New­ton­ian flu­ids is al­so en­coun­tered in many branch­es of en­gi­neer­ing (phys­i­cal chem­istry, blood me­chan­ics, hair gel, corn syrup, oobleck). Those test cas­es fo­cus on the val­i­da­tion of the Pow­er Law mod­el for Non-New­ton­ian flu­ids and the Car­reau and Cross mod­els re­spect­ful­ly (Read more) and (Read more).