Linear and Weakly Nonlinear Instability of Shallow Mixing Layers with Variable Friction

<div>Plot of the <svg height="14.0749pt" id="M146" style="vertical-align:-2.1507pt" version="1.1" viewbox="-0.0498162 -11.9242 16.1365 14.0749" width="16.1365pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M162 -163V703H101V-163H162Z" id="g113-9"></path></g><g transform="matrix(.013,0,0,-0.013,5.213,-2.897)"><path d="M658 624L641 649C599 612 554 595 493 595C444 595 402 603 342 615C268 634 232 641 184 641C129 641 57 621 0 557L17 532C67 566 113 586 176 586C230 586 265 577 316 565C380 550 430 540 482 540C540 540 611 558 658 624Z" id="g119-113"></path></g><g transform="matrix(.013,0,0,-0.013,3.419,0)"><path d="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z" id="g113-66"></path></g><g transform="matrix(.013,0,0,-0.013,12.592,0)"><path d="M162 -163V703H101V-163H162Z" id="g113-9"></path></g></svg> for the case <svg height="9.14241pt" id="M147" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 9.23472 9.14241" width="9.23472pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M383 397C383 424 344 448 299 448C244 448 172 409 132 375C66 319 23 227 23 146C23 42 74 -12 146 -12C208 -12 298 30 359 103L343 124C315 95 248 48 192 48C145 48 111 85 111 163C111 228 129 294 151 330C171 363 201 401 241 401C275 401 302 384 325 356C332 347 339 344 348 348C373 360 383 381 383 397Z" id="g113-100"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.173,3.132)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z" id="g50-50"></path></g></svg> = 1.3294 and <svg height="9.14241pt" id="M148" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -5.96091 9.23472 9.14241" width="9.23472pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M383 397C383 424 344 448 299 448C244 448 172 409 132 375C66 319 23 227 23 146C23 42 74 -12 146 -12C208 -12 298 30 359 103L343 124C315 95 248 48 192 48C145 48 111 85 111 163C111 228 129 294 151 330C171 363 201 401 241 401C275 401 302 384 325 356C332 347 339 344 348 348C373 360 383 381 383 397Z" id="g113-100"></path></g><g transform="matrix(.0091,0,0,-0.0091,4.173,3.132)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z" id="g50-51"></path></g></svg> = 0.1252 (the initial condition corresponds to small random noise).</div>

Advances in Civil Engineering

fig5

Figure 5

Figure 5: Linear and Weakly Nonlinear Instability of Shallow Mixing Layers with Variable Friction 