incompressible fluids - 2023 ACF Nationals

Question

Computational fluid dynamics algorithms for this type of flow must modify basic finite difference methods to prevent the pressure field from oscillating. For 10 points each:

[10m] Name this type of flow whose Mach (“mahk”) number is at or below 0.3.

ANSWER: incompressible fluids [or incompressible flows; or incompressibility; prompt on subsonic fluids or flows]

[10h] The SIMPLE algorithm for incompressible flow uses a staggered grid that calculates pressure at the center of these theoretical structures, while calculating velocity and momentum on their faces. The conservation of the variable of interest within these theoretical structures is expressed by the discretization equation.

ANSWER: control volumes [or cells; or finite volumes; prompt on volumes or finite elements; reject “fluid parcels”]

[10e] The methods based on this quantity for compressible flows are replaced by pressure-based methods for incompressible flows. The buoyant force equals this quantity times “little g” times displaced fluid volume.

ANSWER: mass density [or fluid density; prompt on rho]

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Summary


2023 ACF Nationals	04/22/2023	Y	22	14.09	82%	36%	23%

Data


Yale A	Chicago B	0	0	10	10
Chicago C	Cornell B	0	0	10	10
Claremont A	Yale B	0	0	0	0
MIT A	Columbia A	0	10	10	20
Cornell A	Chicago A	10	0	10	20
Penn State A	Georgia Tech B	10	10	10	30
WUSTL B	Illinois A	0	0	10	10
Rutgers B	Johns Hopkins A	0	0	10	10
Indiana A	Minnesota A	10	0	10	20
Georgia Tech A	Ohio State A	10	0	10	20
Penn A	South Carolina A	0	0	0	0
Purdue A	NYU A	10	0	10	20
Northwestern A	Toronto A	0	10	10	20
Harvard A	UC Berkeley A	0	0	10	10
Imperial A	Vanderbilt A	10	10	10	30
Brown A	Duke A	0	0	10	10
Virginia A	McGill A	0	0	0	0
Texas A	North Carolina A	10	10	10	30
Iowa State A	Rutgers A	0	0	10	10
WUSTL A	Stanford A	0	0	10	10
Michigan A	UC Berkeley B	0	0	0	0
Florida A	Maryland A	10	0	10	20