Systems of BVP with unbalanced BCs












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I have a system of ODEs forming a BVP. I was thinking of using Finite Difference to solve it but for some functions I do not have the BCs on both sides (though in total they are enough to make the problem well stated). I can easily solve the problem with bvp4c in Matlab but I was wondering how to set it up for the Finite Difference method considering indeed that some BCs on the left side are missing.
I thought of shooting but apaprently it can be used only if there is a side where only one BC is missing.
Thank you



The system is:



begin{align}
frac{dx(z)}{dz} &= L(z)cos(theta(z)) \
frac{dy(z)}{dz} &= L(z)sin(theta(z)) \
frac{dtheta(z)}{dz} &= L(z) K(z) \
frac{dK(z)}{dz} &= frac{4 L(z) M(z) U(z)}{3pi} - frac{L(z) K(z) N_3(z)}{3pi} \
frac{dU(z)}{dz} &= frac{L(z) N_3(z) U(z)}{3pi} \
frac{dN_1(z)}{dz} &= - L(z) K(z) N_3(z) + frac{grho a_0^2pi L(z)cos(theta(z))}{eta U_0 U(z)} \
frac{dN_3(z)}{dz} &= L(z) K(z) N_1(z) + frac{grho a_0^2 pi L(z)sin(theta(z))}{eta U_0 U(z)} \
frac{dM(z)}{dz} &= - L(z) N_1(z) + frac{grho a_0^2 pi L(z) K(z)sin(theta(z))} {4eta U_0 U(z)^2} \
frac{dL(z)}{dz} &= 0
end{align}



and the BC are:



$$
begin{aligned}
x(0) &= 0 \
y(0) &= 0 \
theta(0) &= -pi/2 \
U(0) &= 1
end{aligned} quad
begin{aligned}
x(1) &= 10 \
y(1) &= 0 \
theta(1) &= 0 \
U(1) &= 1 \
K(1) &= 0
end{aligned}
$$










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    0












    $begingroup$


    I have a system of ODEs forming a BVP. I was thinking of using Finite Difference to solve it but for some functions I do not have the BCs on both sides (though in total they are enough to make the problem well stated). I can easily solve the problem with bvp4c in Matlab but I was wondering how to set it up for the Finite Difference method considering indeed that some BCs on the left side are missing.
    I thought of shooting but apaprently it can be used only if there is a side where only one BC is missing.
    Thank you



    The system is:



    begin{align}
    frac{dx(z)}{dz} &= L(z)cos(theta(z)) \
    frac{dy(z)}{dz} &= L(z)sin(theta(z)) \
    frac{dtheta(z)}{dz} &= L(z) K(z) \
    frac{dK(z)}{dz} &= frac{4 L(z) M(z) U(z)}{3pi} - frac{L(z) K(z) N_3(z)}{3pi} \
    frac{dU(z)}{dz} &= frac{L(z) N_3(z) U(z)}{3pi} \
    frac{dN_1(z)}{dz} &= - L(z) K(z) N_3(z) + frac{grho a_0^2pi L(z)cos(theta(z))}{eta U_0 U(z)} \
    frac{dN_3(z)}{dz} &= L(z) K(z) N_1(z) + frac{grho a_0^2 pi L(z)sin(theta(z))}{eta U_0 U(z)} \
    frac{dM(z)}{dz} &= - L(z) N_1(z) + frac{grho a_0^2 pi L(z) K(z)sin(theta(z))} {4eta U_0 U(z)^2} \
    frac{dL(z)}{dz} &= 0
    end{align}



    and the BC are:



    $$
    begin{aligned}
    x(0) &= 0 \
    y(0) &= 0 \
    theta(0) &= -pi/2 \
    U(0) &= 1
    end{aligned} quad
    begin{aligned}
    x(1) &= 10 \
    y(1) &= 0 \
    theta(1) &= 0 \
    U(1) &= 1 \
    K(1) &= 0
    end{aligned}
    $$










    share|cite|improve this question











    $endgroup$















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      0








      0





      $begingroup$


      I have a system of ODEs forming a BVP. I was thinking of using Finite Difference to solve it but for some functions I do not have the BCs on both sides (though in total they are enough to make the problem well stated). I can easily solve the problem with bvp4c in Matlab but I was wondering how to set it up for the Finite Difference method considering indeed that some BCs on the left side are missing.
      I thought of shooting but apaprently it can be used only if there is a side where only one BC is missing.
      Thank you



      The system is:



      begin{align}
      frac{dx(z)}{dz} &= L(z)cos(theta(z)) \
      frac{dy(z)}{dz} &= L(z)sin(theta(z)) \
      frac{dtheta(z)}{dz} &= L(z) K(z) \
      frac{dK(z)}{dz} &= frac{4 L(z) M(z) U(z)}{3pi} - frac{L(z) K(z) N_3(z)}{3pi} \
      frac{dU(z)}{dz} &= frac{L(z) N_3(z) U(z)}{3pi} \
      frac{dN_1(z)}{dz} &= - L(z) K(z) N_3(z) + frac{grho a_0^2pi L(z)cos(theta(z))}{eta U_0 U(z)} \
      frac{dN_3(z)}{dz} &= L(z) K(z) N_1(z) + frac{grho a_0^2 pi L(z)sin(theta(z))}{eta U_0 U(z)} \
      frac{dM(z)}{dz} &= - L(z) N_1(z) + frac{grho a_0^2 pi L(z) K(z)sin(theta(z))} {4eta U_0 U(z)^2} \
      frac{dL(z)}{dz} &= 0
      end{align}



      and the BC are:



      $$
      begin{aligned}
      x(0) &= 0 \
      y(0) &= 0 \
      theta(0) &= -pi/2 \
      U(0) &= 1
      end{aligned} quad
      begin{aligned}
      x(1) &= 10 \
      y(1) &= 0 \
      theta(1) &= 0 \
      U(1) &= 1 \
      K(1) &= 0
      end{aligned}
      $$










      share|cite|improve this question











      $endgroup$




      I have a system of ODEs forming a BVP. I was thinking of using Finite Difference to solve it but for some functions I do not have the BCs on both sides (though in total they are enough to make the problem well stated). I can easily solve the problem with bvp4c in Matlab but I was wondering how to set it up for the Finite Difference method considering indeed that some BCs on the left side are missing.
      I thought of shooting but apaprently it can be used only if there is a side where only one BC is missing.
      Thank you



      The system is:



      begin{align}
      frac{dx(z)}{dz} &= L(z)cos(theta(z)) \
      frac{dy(z)}{dz} &= L(z)sin(theta(z)) \
      frac{dtheta(z)}{dz} &= L(z) K(z) \
      frac{dK(z)}{dz} &= frac{4 L(z) M(z) U(z)}{3pi} - frac{L(z) K(z) N_3(z)}{3pi} \
      frac{dU(z)}{dz} &= frac{L(z) N_3(z) U(z)}{3pi} \
      frac{dN_1(z)}{dz} &= - L(z) K(z) N_3(z) + frac{grho a_0^2pi L(z)cos(theta(z))}{eta U_0 U(z)} \
      frac{dN_3(z)}{dz} &= L(z) K(z) N_1(z) + frac{grho a_0^2 pi L(z)sin(theta(z))}{eta U_0 U(z)} \
      frac{dM(z)}{dz} &= - L(z) N_1(z) + frac{grho a_0^2 pi L(z) K(z)sin(theta(z))} {4eta U_0 U(z)^2} \
      frac{dL(z)}{dz} &= 0
      end{align}



      and the BC are:



      $$
      begin{aligned}
      x(0) &= 0 \
      y(0) &= 0 \
      theta(0) &= -pi/2 \
      U(0) &= 1
      end{aligned} quad
      begin{aligned}
      x(1) &= 10 \
      y(1) &= 0 \
      theta(1) &= 0 \
      U(1) &= 1 \
      K(1) &= 0
      end{aligned}
      $$







      boundary-value-problem






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      edited Dec 6 '18 at 9:00









      Dylan

      12.9k31027




      12.9k31027










      asked Nov 30 '18 at 12:31









      acalore88acalore88

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