From 6c9ec4f093ecfa48fe3a4a3fa99de16c5676d7dc Mon Sep 17 00:00:00 2001 From: bnewbold Date: Mon, 16 Jan 2017 16:24:09 -0800 Subject: update remaining models --- examples/van_der_pol_oscillator/model.modelica | 8 ++++++++ examples/van_der_pol_oscillator/page.md | 22 ++++++++++++++++++++++ 2 files changed, 30 insertions(+) create mode 100644 examples/van_der_pol_oscillator/model.modelica create mode 100644 examples/van_der_pol_oscillator/page.md (limited to 'examples/van_der_pol_oscillator') diff --git a/examples/van_der_pol_oscillator/model.modelica b/examples/van_der_pol_oscillator/model.modelica new file mode 100644 index 0000000..c1aa99b --- /dev/null +++ b/examples/van_der_pol_oscillator/model.modelica @@ -0,0 +1,8 @@ +model VanDerPolOscillator + parameter Real mu "dampening strength"; + Real x; + Real y; +equation + der(x) = y; + der(y) = mu * y * (1 - x^2) - x; +end VanDerPolOscillator; diff --git a/examples/van_der_pol_oscillator/page.md b/examples/van_der_pol_oscillator/page.md new file mode 100644 index 0000000..ff24c7c --- /dev/null +++ b/examples/van_der_pol_oscillator/page.md @@ -0,0 +1,22 @@ + +The Van der Pol oscillator was originally proposed by the Dutch electrical +engineer and physicist Balthasar van der Pol while he was working at +Philips. Van der Pol found stable oscillations, which he subsequently +called relaxation-oscillations and are now known as a type of limit cycle in +electrical circuits employing vacuum tubes. When these circuits were driven +near the limit cycle, they become entrained, i.e. the driving signal pulls the +current along with it. Van der Pol and his colleague, van der Mark, reported in +the September 1927 issue of Nature that at certain drive frequencies an +irregular noise was deterministic chaos. + +The Van der Pol equation has a long history of being used in both the physical +and biological sciences. For instance, in biology, Fitzhugh and Nagumo +extended the equation in a planar field as a model for action potentials of +neurons. The equation has also been utilised in seismology to model the two +plates in a geological fault, and in studies of phonation to model the right +and left vocal fold oscillators. + +## References + +* Wikipedia: + [Van der Pol oscillator](https://en.wikipedia.org/wiki/Van_der_Pol_oscillator) -- cgit v1.2.3