ECIV 301 Programming & Graphics Numerical Methods for Engineers Lecture 32 Ordinary Differential Equations
Pendulum W=mg Ordinary Differential Equation
ODEs Non Linear Linearization Assume is small
ODEs Second Order Systems of ODEs
ODE
ODE - OBJECTIVES Undetermined
ODE- Objectives Initial Conditions
ODE-Objectives Given Calculate
Runge-Kutta Methods New Value = Old Value + Slope X Step Size
Runge Kutta Methods Definition of yields different Runge-Kutta Methods
Euler’s Method Let
Sources of Error Truncation: Caused by discretization Local Truncation Propagated Truncation Roundoff: Limited number of significant digits
Sources of Error Propagated Local
Euler’s Method
Heun’s Method PredictorCorrector 2-Steps
Heun’s Method Predict Predictor-Corrector Solution in 2 steps Let
Heun’s Method Correct Corrector Estimate Let
Error in Heun’s Method
The Mid-Point Method Remember: Definition of yields different Runge-Kutta Methods
Mid-Point Method Predictor Corrector 2-Steps
Mid-Point Method Predictor Predict Let
Mid-Point Method Corrector Correct Estimate Let
Runge Kutta – 2 nd Order
Runge Kutta – 3rd Order
Runge Kutta – 4th Order
Boundary Value Problems
Fig 23.1 FORWARD FINITE DIFFERENCE
Fig 23.2 BACKWARD FINITE DIFFERENCE
Fig 23.3 CENTERED FINITE DIFFERENCE
xoxo Boundary Value Problems x1x1 x2x2 x3x3 x n-1 xnxn...
Boundary Value Problems xoxo x1x1 x2x2 x3x3 x n-1 xnxn...
Boundary Value Problems xoxo x1x1 x2x2 x3x3 x n-1 xnxn...
Boundary Value Problems xoxo x1x1 x2x2 x3x3 x n-1 xnxn...
Boundary Value Problems xoxo x1x1 x2x2 x3x3 x n-1 xnxn...
Boundary Value Problems Collect Equations: BOUNDARY CONDITIONS
Example x1x1 x2x2 x3x3 x4x4