Mech 3031 - compute the reynolds numbers and drag

Question

Problem

Spheres will be placed in the wind tunnel and tested over a wide range of airspeeds to see how their drag varies with the airspeed. Create a Microsoft Excel spreadsheet that can be used to take the data collected in the wind tunnel and compute the Reynolds numbers and drag coefficients.

Both the vacuum and the dynamic pressure were measured using Dwyer gage-oil manometers scaled to read millimeters of water. Assume the density of the liquid in these manometers is ρ_m, =1000 kg/m³ when you compute the pressure difference with the hydrostatic formula, Δρ = (ρ_m - ρ_a)gh. A standard metric mass was used to calibrate the drag-beam dynamometer, and the drag force MD displayed by the dynamometer is in kilograms. Use F_D = M_Dg to put the drag force in newtons.

Use the attached sample as a guide for the proper formatting of your spreadsheet. On the attached sample spreadsheet all of the numerical values in the first four columns are input values, and all of the numerical values to the right of the first four columns have been computed using cell formulas. Your spreadsheet should have this same feature. For example, the sphere's diameter will be input in millimeters and the spreadsheet will compute the frontal area in m², so that when the value for D is changed the area will automatically change. Everything to the right of the first four columns must change automatically with changes in input values.

Smooth Sphere Drag Coefficients
INPUT VALUES			COMPUTED VALUES
h bar =	624	mm	SG Hg=	13.5544
T =	19	°C	ρ Hg =	13554	kg/m3
D =	75.6	mm	P atm =	82854	Pa
			T abs =	292.15	K
g in lab =	9.796	m/s2	A =	0.004489	m2
ρm - ρa=	999	kg/m3	μ =	1.809E-05	Pa-s

Motor
Frequency	h dynamic	h vacuum	MD	P dynamic	P vacuum	FD	P absolute	p air	V
Hz	mm	mm	kg	Pa	Pa	N	Pa	kg/m3	in/sec	Re D	CD
20	13	18	0.03	127.2	176	0.2939	82678	0.9864	16.06	66221	0.515
25	21.2	28	0.047	207.5	274	0.4604	82580	0.9852	20.52	84515	0.494
30	31.5	40	0.069	308.3	391	0.6759	82463	0.9838	25.03	102947	0.488
35	43.5	56	0.095	425.7	548	0.9306	82306	0.982	29.45	120862	0.487
40	57.8	72	0.127	565.6	705	1.2441	82149	0.9801	33.97	139186	0.49
45	74	88	0.161	724.2	861	1.5772	81993	0.9782	38.48	157338	0.485
50	92.3	112	0.203	903.3	1096	1.9886	81758	0.9754	43.04	175467	0.49
55	112.6	134	0.254	1101.9	1311	2.4882	81543	0.9729	47.6	193549	0.503
60	134.5	160	0.309	1316.2	1566	3.027	81288	0.9698	52.1	211205	0.512