Appendix/Ramblings/51BiPolytropeStability/NoAnalytic: Difference between revisions

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In an [[SSC/Stability/BiPolytropes#Fundamental_Modes|accompanying discussion]], we claim to have identified at what point along various <math>\mu_e/\mu_c</math> sequences the fundamental mode of radial oscillation becomes unstable &#8212; that is, when <math>\sigma_c^2 = 0</math>.  For a given choice of <math>\mu_e/\mu_c</math>, it would be wise to begin our eigenvector search at a value of <math>\xi_i</math> that is smaller than specified in the following table:
In an [[SSC/Stability/BiPolytropes#Fundamental_Modes|accompanying discussion]], we claim to have identified at what point along various <math>\mu_e/\mu_c</math> sequences the fundamental mode of radial oscillation becomes unstable &#8212; that is, when <math>\sigma_c^2 = 0</math>.  For a given choice of <math>\mu_e/\mu_c</math>, it would be wise to begin our eigenvector search at a value of <math>\xi_i</math> that is smaller than specified in the following table:
<table border="1" cellpadding="10" align="center">
<table border="1" cellpadding="10" align="center" width="40%">
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<tr>
   <td align="center"><math>\frac{\mu_e}{\mu_c}</math></td>
   <td align="center"><math>\frac{\mu_e}{\mu_c}</math></td>
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   <td align="center"><math>\tfrac{1}{4}</math></td>
   <td align="center"><math>\tfrac{1}{4}</math></td>
   <td align="right">2.7357711469398</td>
   <td align="right">2.7357711469398</td>
</tr>
<tr>
  <td align="left" colspan="2">See orange-colored triangular markers in the associated [[SSC/Stability/BiPolytropes#Figure4|Figure 4]]</td>
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</table>  
</table>  

Revision as of 19:37, 19 July 2022

Do Not Confine Search to Analytic Eigenvector

Overview

STEP01:
Develop an algorithm (for Excel) that numerically integrates the LAWEs from the center to the surface of a (nc,ne)=(5,1) bipolytrope, for an arbitrary specification of the three parameters:   μe/μc,ξi, and σc2.

  • Enforce the proper interface matching condition(s) at the interface location, ξi.
  • Note that in general, for an arbitrarily chosen set of the three parameter values, the resulting surface displacement function will not match the desired boundary condition.

STEP02:
Fix your chosen value of the parameter pair, (μe/μc,ξi), and vary σc2 until the proper surface boundary condition is realized.

  • In an accompanying discussion, we claim to have identified at what point along various μe/μc sequences the fundamental mode of radial oscillation becomes unstable — that is, when σc2=0. For a given choice of μe/μc, it would be wise to begin our eigenvector search at a value of ξi that is smaller than specified in the following table:
    μeμc ξi
    1 1.6686460157
    12 2.27925811317
    0.345 2.560146865247
    13 2.582007485476
    0.309 2.6274239687695
    14 2.7357711469398
    See orange-colored triangular markers in the associated Figure 4

See Also

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