Minimising a complex equation












1












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I'm trying to find a way to find a value(s) of $omega$ which minimise



$$mathbb{R} = 1 - frac{1+R_0^4-2R_0^2}{1+R_0^4 -2R_0^2cos(2omegabeta_1 L)}.$$



The terms in the equation depend on $omega$, namely



$$R_0 = frac{barrho_0sqrt{frac{bar rho_1}{c_{44}}}+barrho_1 sqrt{frac{barrho_1}{mu_0}}}{bar rho_1 sqrt{frac{bar rho_0}{mu_0}}-bar rho_0 sqrt{frac{bar rho_1}{c_{44}}}}$$



where



$$beta_1 = sqrt{frac{bar rho_1}{c_{44}}},$$



$$bar rho_0 = rho_0 - frac{k_1^2mu_0}{omega^2},$$



$$bar rho_1 = rho_1 - frac{k_1^2c_{66}}{omega^2}-frac{k_1^2c_{64}^2}{omega^2 c_{44}},$$



$$bar rho_2 = rho_2 - frac{k_1^2mu_2}{omega^2}.$$



The constants in this equation are



$$mu_{0,2}, rho_{0,1,2}, c_{44}, c_{64},c_{66},k_1,L$$



Am I in over my head here? Is there anything I could do to make analytical headway?










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  • $begingroup$
    It looks really ugly. Where did it come from? Continuum mechanics?
    $endgroup$
    – Botond
    Jan 31 at 21:41










  • $begingroup$
    Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
    $endgroup$
    – rodger_kicks
    Jan 31 at 21:45
















1












$begingroup$


I'm trying to find a way to find a value(s) of $omega$ which minimise



$$mathbb{R} = 1 - frac{1+R_0^4-2R_0^2}{1+R_0^4 -2R_0^2cos(2omegabeta_1 L)}.$$



The terms in the equation depend on $omega$, namely



$$R_0 = frac{barrho_0sqrt{frac{bar rho_1}{c_{44}}}+barrho_1 sqrt{frac{barrho_1}{mu_0}}}{bar rho_1 sqrt{frac{bar rho_0}{mu_0}}-bar rho_0 sqrt{frac{bar rho_1}{c_{44}}}}$$



where



$$beta_1 = sqrt{frac{bar rho_1}{c_{44}}},$$



$$bar rho_0 = rho_0 - frac{k_1^2mu_0}{omega^2},$$



$$bar rho_1 = rho_1 - frac{k_1^2c_{66}}{omega^2}-frac{k_1^2c_{64}^2}{omega^2 c_{44}},$$



$$bar rho_2 = rho_2 - frac{k_1^2mu_2}{omega^2}.$$



The constants in this equation are



$$mu_{0,2}, rho_{0,1,2}, c_{44}, c_{64},c_{66},k_1,L$$



Am I in over my head here? Is there anything I could do to make analytical headway?










share|cite|improve this question











$endgroup$












  • $begingroup$
    It looks really ugly. Where did it come from? Continuum mechanics?
    $endgroup$
    – Botond
    Jan 31 at 21:41










  • $begingroup$
    Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
    $endgroup$
    – rodger_kicks
    Jan 31 at 21:45














1












1








1





$begingroup$


I'm trying to find a way to find a value(s) of $omega$ which minimise



$$mathbb{R} = 1 - frac{1+R_0^4-2R_0^2}{1+R_0^4 -2R_0^2cos(2omegabeta_1 L)}.$$



The terms in the equation depend on $omega$, namely



$$R_0 = frac{barrho_0sqrt{frac{bar rho_1}{c_{44}}}+barrho_1 sqrt{frac{barrho_1}{mu_0}}}{bar rho_1 sqrt{frac{bar rho_0}{mu_0}}-bar rho_0 sqrt{frac{bar rho_1}{c_{44}}}}$$



where



$$beta_1 = sqrt{frac{bar rho_1}{c_{44}}},$$



$$bar rho_0 = rho_0 - frac{k_1^2mu_0}{omega^2},$$



$$bar rho_1 = rho_1 - frac{k_1^2c_{66}}{omega^2}-frac{k_1^2c_{64}^2}{omega^2 c_{44}},$$



$$bar rho_2 = rho_2 - frac{k_1^2mu_2}{omega^2}.$$



The constants in this equation are



$$mu_{0,2}, rho_{0,1,2}, c_{44}, c_{64},c_{66},k_1,L$$



Am I in over my head here? Is there anything I could do to make analytical headway?










share|cite|improve this question











$endgroup$




I'm trying to find a way to find a value(s) of $omega$ which minimise



$$mathbb{R} = 1 - frac{1+R_0^4-2R_0^2}{1+R_0^4 -2R_0^2cos(2omegabeta_1 L)}.$$



The terms in the equation depend on $omega$, namely



$$R_0 = frac{barrho_0sqrt{frac{bar rho_1}{c_{44}}}+barrho_1 sqrt{frac{barrho_1}{mu_0}}}{bar rho_1 sqrt{frac{bar rho_0}{mu_0}}-bar rho_0 sqrt{frac{bar rho_1}{c_{44}}}}$$



where



$$beta_1 = sqrt{frac{bar rho_1}{c_{44}}},$$



$$bar rho_0 = rho_0 - frac{k_1^2mu_0}{omega^2},$$



$$bar rho_1 = rho_1 - frac{k_1^2c_{66}}{omega^2}-frac{k_1^2c_{64}^2}{omega^2 c_{44}},$$



$$bar rho_2 = rho_2 - frac{k_1^2mu_2}{omega^2}.$$



The constants in this equation are



$$mu_{0,2}, rho_{0,1,2}, c_{44}, c_{64},c_{66},k_1,L$$



Am I in over my head here? Is there anything I could do to make analytical headway?







calculus optimization classical-mechanics






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share|cite|improve this question













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edited Jan 31 at 21:44









gt6989b

35.6k22557




35.6k22557










asked Jan 31 at 21:38









rodger_kicksrodger_kicks

11010




11010












  • $begingroup$
    It looks really ugly. Where did it come from? Continuum mechanics?
    $endgroup$
    – Botond
    Jan 31 at 21:41










  • $begingroup$
    Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
    $endgroup$
    – rodger_kicks
    Jan 31 at 21:45


















  • $begingroup$
    It looks really ugly. Where did it come from? Continuum mechanics?
    $endgroup$
    – Botond
    Jan 31 at 21:41










  • $begingroup$
    Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
    $endgroup$
    – rodger_kicks
    Jan 31 at 21:45
















$begingroup$
It looks really ugly. Where did it come from? Continuum mechanics?
$endgroup$
– Botond
Jan 31 at 21:41




$begingroup$
It looks really ugly. Where did it come from? Continuum mechanics?
$endgroup$
– Botond
Jan 31 at 21:41












$begingroup$
Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
$endgroup$
– rodger_kicks
Jan 31 at 21:45




$begingroup$
Yes it's a result from a wave problem. I'm trying to find a way to minimise this to take fourier transform to look at waves in time domain...
$endgroup$
– rodger_kicks
Jan 31 at 21:45










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