19. Lurch 4 Angularadd 3-D motion of large fragments

The model and its justification
    Lurch 4 Angular is the rotational analog of Lurch 4 Linear. As with Lurch 3 Angular, it calculates the speed of the rearward lurch from the bullet, the body, the conical cloud, large fragments, and the large fragments. To this it adds 3-D motion of the large fragments. This addition barely changes the results, with the rearward lurch decreasing in strength from 1.44 ft s-1 to 1.38 ft s-1. This change amounts to only 4%, and means that the 3-D motion of the large fragments is an unimportant part of the solution. A similar result was found for the linear calculations.

Solving the simultaneous equations
    

 

Conservation of angular X-momentum

 

Conservation of total energy

Default values of variables

mbullet = 161 gr

vbullet = 1800 ft s-1

mfrag1 = 0.027 gr

mbody = 85 lb

vbulletafter = 200 ft s-1

mfrags23 = 0.01 gr

mcloud = 0.3 lb

Qfrag1 = 40°

vfrag1 = 500 ft s-1

Q = 17°

Qfrags23 = 70°

vfrags23 = 500 ft s-1

PE = 200 ft-lb

Qcl = 70°

fkefrag1 = 1.25

fI = 1.11

 

fkefrags23 = 1.25

Solutions to simultaneous equations

vbodyafter = -1.38 ft s-1  vcloud = 378 ft s-1

Distributions of momentum and energy

Angular momentum

Energy, ft-lb

Before

After

Before

After

Ωbullet = 3.80

Ωbulletafter = 0.43

KEbullet = 1164

KEbulletafter = 14

 

Ωbodyafter = -4.05

 

KEbodyafter = 1

 

Ωcloud = 6.28

 

KEcloud = 668

 

Ωfrag1 = 0.97

 

KEfrag1 = 132

 

Ωfrags23 = 0.16

 

KEfrags23 = 49

 

 

 

PE = 300

 

Sensitivity analysis
    

Sensitivity analysis, Lurch 4 angular
(Standard conditions in boldface)

mbullet

vlurch

mbody

vlurch

mcloud

vlurch

PE

vlurch

vbullet

vlurch

 

 

 

 

 

 

0

-1.813

 

 

156

-1.356

 

 

 

 

50

-1.746

1750

-1.310

157

-1.361

65

-1.804

 

 

100

-1.677

1760

-1.324

158

-1.365

70

-1.675

 

 

150

-1.606

1770

-1.337

159

-1.370

75

-1.563

0.1

-0.474

200

-1.532

1780

-1.351

160

-1.374

80

-1.465

0.2

-0.985

250

-1.457

1790

-1.365

161

-1.378

85

-1.378

0.3

-1.378

300

-1.378

1800

-1.378

162

-1.383

90

-1.301

0.4

-1.710

350

-1.297

1810

-1.392

163

-1.387

95

-1.233

0.5

-2.003

400

-1.212

1820

-1.405

164

-1.391

100

-1.171

0.6

-2.269

450

-1.124

1830

-1.418

165

-1.395

105

-1.115

0.7

-2.513

500

-1.031

1840

-1.432

166

-1.399

 

 

0.8

-2.742

550

-0.933

1850

-1.445

 

 

 

 

 

 

600

-0.828

 

 

Sensitivity = 
[(-1.383 + 1.374)/2]/
[1.378/161] = -0.53

Sensitivity = 
[(-1.301 + 1.465)/10]/
[1.378/85] = 1.01

Sensitivity = 
[(-1.710 + 0.985)/0.2]/
[1.378/0.3] = -0.79

Sensitivity = 
[(-1.297 + 1.457)/100]/
[1.378/300] = 0.35

Sensitivity = 
[(-1.392 + 1.365)/20]/
[1.378/1800] = -1.76

Range = 0.04

Range = 0.69

Range = 2.27

Range = 0.98

Range = 0.14

vbulletafter

vlurch

Q

vlurch

Qcl

vlurch

mfrag1

vlurch

mfrags23

vlurch

 

 

7

-1.359

20

-2.704

0.022

-1.356

0.005

-1.390

0

-1.255

8

-1.362

30

-2.531

0.023

-1.360

0.006

-1.387

50

-1.290

9

-1.366

40

-2.301

0.024

-1.365

0.007

-1.385

100

-1.322

10

-1.369

50

-2.023

0.025

-1.369

0.008

-1.383

150

-1.352

11

-1.374

60

-1.701

0.026

-1.374

0.009

-1.381

200

-1.378

12

-1.378

70

-1.378

0.027

-1.378

0.010

-1.378

250

-1.402

13

-1.383

80

-1.038

0.028

-1.383

0.011

-1.376

300

-1.423

14

-1.389

90

-0.705

0.029

-1.387

0.012

-1.374

350

-1.440

15

-1.394

100

-0.391

0.030

-1.391

0.013

-1.371

400

-1.455

16

-1.401

110

-0.106

0.031

-1.396

0.015

-1.369

 

 

17

-1.407

120

+0.142

0.032

-1.400

0.015

-1.366

Sensitivity = 
[(-1.402 + 1.352)/100]/
[1.378/200] = -0.07

Sensitivity = 
[(-1.389 + 1.369)/4]/
[1.378/12] = -0.04

Sensitivity = 
[(-1.038 + 1.711)/20]/
[1.378/70] = 1.71

Sensitivity = 
[-1.383 + 1.374)/0.002]/
[1.378/0.027] = -0.09

Sensitivity = 
[(-1.374 + 1.383)/0.004]/
[1.378/0.010] = 0.02

Range = 0.20

Range = 0.05

Range = 2.85

Range = 0.04

Range = 0.02

vfrag1

vlurch

vfrags23

vlurch

Qfrag1

vlurch

Qfrags23

vlurch

fkefrag1

vlurch

250

-1.366

250

-1.409

 

 

 

 

1.00

-1.420

300

-1.377

300

-1.406

20

-1.453

50

-1.426

1.05

-1.412

350

-1.384

350

-1.401

25

-1.439

55

-1.415

1.10

-1.403

400

-1.387

400

-1.395

30

-1.421

60

-1.403

1.15

-1.395

450

-1.385

450

-1.388

35

-1.401

65

-1.391

1.20

-1.387

500

-1.378

500

-1.378

40

-1.378

70

-1.387

1.25

-1.378

550

-1.367

550

-1.367

45

-1.353

75

-1.365

1.30

-1.370

600

-1.349

600

-1.355

50

-1.325

80

-1.351

1.35

-1.361

650

-1.327

650

-1.340

55

-1.295

85

-1.338

1.40

-1.353

700

-1.297

700

-1.324

60

-1.264

90

-1.324

1.45

-1.344

700

-1.261

750

-1.306

 

 

 

 

1.50

-1.336

Sensitivity = 
[(-1.367 + 1.385)/100]/
[1.378/500] = 0.06

Sensitivity = 
[(-1.367 + 1.388)/100]/
[1.378/500] = 0.08

Sensitivity = 
[(-1.353 + 1.401)/10]/
[1.378/40] = 0.14

Sensitivity = 
[(-1.365 + 1.391)/10]/
[1.378/70] = 0.13

Sensitivity = 
[(-1.370 + 1.387)/0.10]/
[1.378/1.25] = 0.15

Range = 0.10

Range = 0.10

Range = 0.19

Range = 0.10

Range = 0.08

fkefrags23

vlurch

fI

vlurch

1.00

-1.394

1.06

-1.443

1.05

-1.391

1.07

-1.430

1.10

-1.388

1.08

-1.417

1.15

-1.384

1.09

-1.404

1.20

-1.381

1.10

-1.391

1.25

-1.378

1.11

-1.378

1.30

-1.375

1.12

-1.366

1.35

-1.372

1.13

-1.354

1.40

-1.369

1.14

-1.342

1.45

-1.366

1.15

-1.330

1.50

-1.363

1.16

-1.319

Sensitivity = 
[(-1.375 + 1.381)/0.10]/
[1.378/1.25] = 0.05

Sensitivity = 
[(-1.366 + 1.391)/0.02]/
[1.378/1.11] = 1.01

Range = 0.03

Range = 0.12