Monday, April 1, 2013

Kinetic Energy Factors of Dynamic Atmosphere - 21st Century Meteorology Wind Scale

Rev.2  Jan.2018
Greater public safety should be achieved if storm forecasting emphasis is placed on kinetic energy of wind, instead of speed. From the kinetic energy factors presented herein, a user gains understanding and appreciation for the forces of strong winds.


Kinetic Energy Factors of Wind - Table I
Relative
Wind Speed
Reference Wind Scales
Kinetic Energy
km/hr
mi/hr
knots
Beaufort
Saffir-Simpson
Fujita EF
0.56
75
47
41
Gale 9
 
 
0.62
79
49
43
"
 
 
0.68
83
51
45
"
 
 
0.75
87
54
47
"
 
 
0.83
91
56
49
Storm 10
 
 
0.91
95
59
51
"
 
 
1.0
100
62
54
"
 
 
1.1
105
65
57
Storm 11
 
0
1.2
110
68
59
"
 
"
1.3
115
72
62
"
 
"
1.5
121
75
65
Hurcn 12
1
"
1.6
127
79
69
"
"
"
1.8
133
83
72
"
"
"
1.9
140
87
75
 
"
1
2.1
146
91
79
 
"
"
2.4
154
95
83
 
"
"
2.6
161
100
87
 
2
"
2.9
169
105
91
 
"
"
3.1
177
110
96
 
"
"
3.5
186
115
100
 
3
2
3.8
195
121
105
 
"
"
4.2
204
127
110
 
"
"
4.6
214
133
116
 
4
"
5.1
225
140
121
 
"
3
5.6
236
147
127
 
"
"
6.1
247
154
134
 
"
"
6.7
259
161
140
 
5
"
7.4
272
169
147
 
"
4
8.1
285
177
154
 
"
"
9.0
299
186
162
 
"
"
9.8
314
195
169
 
"
"
10.8
329
205
178
 
"
5
11.9
345
215
186
 
"
"
13.1
362
225
196
 
"
"
14.4
380
236
205
 
"
"
15.9
398
247
215
 
"
"
17.4
418
260
226
 
"
"
19.2
438
272
237
 
"
"
21.1
459
286
248
 
"
"
23.2
482
299
260
 
"
"
25.5
505
314
273
 
"
"
28.1
530
329
286
 
"
"
30.9
556
345
300
 
"
"
34.0
583
362
315
 
"
"
37.4
612
380
330
 
"
"
41.1
641
399
346
 
"
"
Kinetic energy of wind increases by 10% over each preceding step.
WF Cade             TinyURL.com/WxPro             Rev.2 ©Jan.2018

 
Theory
Within this article, wind is modeled as a volume of moving atmospheric gases, with each molecule acting as a single projectile.

Kinetic energy is defined from classical physics, as follows;
E =(1/2)[MV2]

Where; E = "kinetic energy of motion", M = "mass of projectile", V = "velocity of projectile"


The exact mass of a strong wind is uncertain. Consequently, it is virtually impossible to calculate its absolute kinetic energy. However the task is made easy to accomplish, by specifying its kinetic energy relative to a standard magnitude.

The author has selected a base reference from the metric system, which is the modern system of measurement. Consequently the wind velocity of 100 km/hr is defined to possess a kinetic energy of one.

To appreciate a kinetic energy 1.0 wind, try the following experiment. As a passenger in an automobile, which is legally traveling at 100 km/hr (62 mi/hr), hold a hand out the window. With your palm facing forward and held fully open, feel and evaluate the force of such a wind. To be more precise, try this on a day when the local area wind is dead calm.

Scale design should clearly indicate changes in kinetic energy, which are associated with changes in wind velocity. For document Rev.2, the author chose to utilize an energy multiplier of 1.1 for each step. Therefore, any kinetic energy step is 10% greater in magnitude, than the preceding step.

Consequently, kinetic energy of the measured wind exhibits a ten-percent compounded growth rate throughout Table-I. Note that previously published versions of this article utilized 20% kinetic energy steps instead. However, the base wind reference velocity and fundamental equations are identical for all versions.

From any initial step, such a scale approximately doubles in energy magnitude, for every seven-step increase. For example;  (1.1)7 = 1.95

For the wind to be measured, let “E” represent kinetic energy, “M” represent mass and “V” represent velocity.

Therefore, the measured wind has kinetic energy; E = 1/2[MV2]

For the reference wind, let “e” represent kinetic energy, “m” represent mass and “v” represent velocity.


Therefore, the specified reference wind has kinetic energy; e = 1/2[mv2]

As a pure thought experiment, consider the wind from any storm with velocity V and instantaneously apply the brakes. As a result, the same wind now possesses the reference velocity of 100 km/hr.

Moreover, mass  M = m  because the measured wind is identical to the reference wind in every respect, except for velocity. Due to cancellation of both the mass and constant terms in the equations which follow, it becomes apparent that the kinetic energy of wind can be expressed as a ratio.

Kinetic energy ratios or force factors of wind; K
K = E/e
K = 1/2[MV2] / 1/2[mv2]
K = V2/v2    ; Eq.1

Solve function Eq.1 for velocity; V
K = V2/v2
V2 = Kv2
V= v[K1/2]    ; Term K1/2 equals square-root of K
V =  (v)K   ; Eq.2


For all computations herein, wind velocity must be expressed in metric units of km/hr. Wind velocity (speed) conversion factors follow. Moreover, wind velocity v is defined as 100 km/hr.

(km/hr) = (1.852) x (knots)
(km/hr) = (1.609) x (mi/hr)


Evaluate function Eq.1 for kinetic energy factor; K
K = V2/v2
K = V2/(100)2
K = V2/(10,000)    ; Eq.3

Evaluate function Eq.2 for measured wind velocity V;
V =  (v)K
V =  (100)K   ; Eq.4


Function Eq.3 is the innovative wind gauge and significant tool for charting or graphing the kinetic energy development of hurricanes and typhoons. Whereby; Meteorologists can compute Cade Kinetic Energy Factors, for any desired wind.

Within Table-I, column one step elements for "K" are employed as independent variables to determine metric wind velocity. Consequently as functions of the associated "K" factors, the solution set for “V" is computed by function Eq.4.

From Beaufort, Saffir-Simpson and Fajita scales, applicable data elements are mapped onto Table-I. However, some elements of the referenced scales may have fallen between calculated kinetic energy steps and thus do not appear. The Beaufort scale is mapped by wind speed in knots; whereas, the Saffir-Simpson and Fijita Operational EF scales are mapped by miles per hour.


If any measured wind is compared to the reference wind, its calculated “K” factor reports the relative energy multiplier. However, the solution set for K has no units and is only a relative scale. As a function of kinetic energy factors, calculated velocities (speeds) of all winds within Table-I are rounded to the nearest integer value.

The kinetic energy of wind increases in direct proportion to the square of its velocity. As an example, consider a hurricane with the wind speed of 100 mi/hr. From Table-I , the associated multiplier or factor is 2.6. By relative measure, such a storm possesses 2.6 times greater kinetic energy than the reference wind.

But when the same storm increases by seven-steps to 140 mi/hr, the kinetic energy factor becomes 5.1.  Due to a square-law relationship, this 40 mi/hr wind speed increase yields about twice the kinetic energy or force.


Ultimately, innovation must be recognized. A truly good idea can overcome academic inertia and contribute to science; thus making the world a better place.


Conclusion
At a single instant in time, the total wind kinetic energy expended upon a structure equals the summation of impact energies, of each gas molecule. Consequently, it is unnecessary to determine the grand total kinetic energy of such storms. Instead, a novel tool is provided herein for gauging the relative kinetic energy of wind.

Although the total mass of a hurricane often increases daily, the mass contained in any very thin vertical sheet of wind gases is relatively constant. Therefore, comparisons made between different storms will yield valid results. If wind velocity is charted daily, any single storm can be trended for such kinetic energy changes.

In classical physics, velocity V is specified by a vector, which exhibits both magnitude and direction. However within this article, atmospheric gas molecules are considered to be moving horizontally along the positive "x" axis, while both "y" and "z" axis components are zero.


Moreover, both the measured and reference winds are considered to be moving parallel in the same direction, which is a reasonable conclusion. Thus within Table-I, the vector term of "velocity" is replaced with "speed" instead.

Alternative Derivation
Cade Kinetic Energy Factors of Wind

E = (1/2)MV2 ; kinetic energy from classical physics

Since atmospheric mass M, per unit volume, is specified by density ρ (rho);
E = (1/2)
ρV2 ; kinetic energy of air

The following general physics formula for wind force (F) applies to large billboards or the surface of a building;
F= EAC = [(1/2)
ρV2]AC
F = (1/2)
ρACV2

Definitions;
K = Force ratios of wind or force factors
C = Wind drag coefficient of object

ρ = Mass density of air
A = Frontal surface area of object
Fm = Measured wind force*
Fr = Reference wind force*
V = Measured wind velocity; by km/hr units
v = Reference wind velocity; definition 100 km/hr
*    Wind direction perpendicular to plane of object


Solve for K to make force comparison;
K = Fm / Fr
K = [(1/2)
ρACV2] / [(1/2)ρACv2]

Equal terms (1/2), ρ, A, and C cancel out;
K = V2/ v2
K = V2/ (100)2
K = V2/(10,000)

Note: Factor K is identical to Cade function Eq.3.


Property Rights
WF Cade, the inventor of Cade Kinetic Energy Factors of Wind, reserves all herein related engineering science technology patents and copyrights; ©2005 ©2012 ©2013 ©2014. Moreover; the inventor revised, rescaled and re-copyrighted said Rev.2 invention documents ©Jan.2018.

For any business or commercial broadcast meteorology purposes, an applicable business license shall be required for transmission of said gauge data over any; radio, television, telephone, satellite, internet, or other mediums.

However, the following exceptions apply;

Any agency of the United States Federal Government, such as the National Oceanic and Atmospheric Administration, Federal Aviation Administration, Air Force, Army, Navy, Marines, and Coast Guard is permanently exempt from any license requirement.

With proper credit, authors of weather science or meteorology textbooks are authorized to publish the gauge design theory herein and the associated tables of kinetic energy factors for wind.

Moreover; with proper credit, the engineering science analysis and weather physics data contained herein may be utilized world-wide by any; official government weather bureau, educational institution, professor, teacher, student, amateur weather forecaster, storm chaser, amateur (ham) radio operator or individual. Such afore named users are encouraged to utilize the gauge design presented herein and provide web links to this page.


Reference Links
Beaufort Wind Storm Scale; National Weather Service
https://www.weather.gov/mfl/beaufort

Saffir-Simpson Hurricane Wind Scale; National Weather Service:
https://www.weather.gov/hgx/tropical_scale


Fujita Extended Tornado Scale; National Oceanic and Atmospheric Administration.
http://www.spc.noaa.gov/efscale/


Great Hurricanes of History; National Oceanic and Atmospheric Administration
Harvey, Irma, Andrew, Wilma, Rita, Katrina, Martinique, Juan, Jeanne, Ivan, Isabel, Ike, Hugo, Gutav, Galveston Tx,, Frances, Floyd, Fifi, Dominican Republic, Charley, Andrew and The Great Hurricane.
http://www.nhc.noaa.gov/outreach/history/


Appendix
Data within Table-II below utilizes the same algebraic functions and 100 km/hr wind base reference as Table-I.  But function Eq.3 serves instead to compute column one elements, by utilizing metric wind velocity as the independent variable in 10 km/hr intervals.

Both work well and consequently, table selection is a matter of intended application and personal preference. However, the seven-step energy doubling rule does not apply to Table-II data.



Kinetic Energy Factors of Wind - Table II
Relative
Wind Speed
Reference Wind Scales
Kinetic Energy
km/hr
mi/hr
knots
Beaufort
Saffir-Simpson
Fujita EF
0.49
70
43
38
Gale 8
 
 
0.64
80
50
43
Gale 9
 
 
0.81
90
56
49
Storm 10
 
 
1.0
100
62
54
"
 
 
1.2
110
68
59
Storm 11
 
0
1.4
120
75
65
Hurcn 12
1
"
1.7
130
81
70
 
"
"
2.0
140
87
76
 
"
1
2.3
150
93
81
 
"
"
2.6
160
99
86
 
2
"
2.9
170
106
92
 
"
"
3.2
180
112
97
 
3
2
3.6
190
118
103
 
"
"
4.0
200
124
108
 
"
"
4.4
210
130
113
 
4
"
4.8
220
137
119
 
"
3
5.3
230
143
124
 
"
"
5.8
240
149
130
 
"
"
6.3
250
155
135
 
"
"
6.8
260
162
140
 
5
"
7.3
270
168
146
 
"
4
7.8
280
174
151
 
"
"
8.4
290
180
157
 
"
"
9.0
300
186
162
 
"
"
9.6
310
193
167
 
"
"
10.2
320
199
173
 
"
"
10.9
330
205
178
 
"
5
11.6
340
211
184
 
"
"
12.3
350
217
189
 
"
"
13.0
360
224
194
 
"
"
13.7
370
230
200
 
"
"
14.4
380
236
205
 
"
"
15.2
390
242
211
 
"
"
16.0
400
249
216
 
"
"
16.8
410
255
221
 
"
"
17.6
420
261
227
 
"
"
18.5
430
267
232
 
"
"
19.4
440
273
238
 
"
"
20.3
450
280
243
 
"
"
21.2
460
286
248
 
"
"
22.1
470
292
254
 
"
"
23.0
480
298
259
 
"
"
24.0
490
304
265
 
"
"
25.0
500
311
270
 
"
"
26.0
510
317
275
 
"
"
27.0
520
323
281
 
"
"
28.1
530
329
286
 
"
"
29.2
540
336
292
 
"
"
30.3
550
342
297
 
"
"
31.4
560
348
302
 
"
"
32.5
570
354
308
 
"
"
33.6
580
360
313
 
"
"
34.8
590
367
319
 
"
"
36.0
600
373
324
 
"
"
37.2
610
379
329
 
"
"
38.4
620
385
335
 
"
"
39.7
630
391
340
 
"
"
41.0
640
398
346
 
"
"
Data Charted as a Function of Wind Speed in Steps of 10 Km/Hr
WF Cade             TinyURL.com/WxPro             Rev.2 ©Jan.2018