diff --git a/README.md b/README.md index d4b893e8..a4547929 100644 --- a/README.md +++ b/README.md @@ -161,3 +161,4 @@ Unit tests should *not* be uploaded to this repository. Please put them in the ` - [Convection gaussian hill problem](convection_diffusion/validation/gaussian_hill_explicit) - [Convection-Diffusion gaussian hill problem](convection_diffusion/validation/gaussian_hill_with_diffusion_explicit) - [Rotating pulse problem](convection_diffusion/validation/rotating_pulse_explicit) +- [Space and time convergence tests](convection_diffusion/validation/space_time_convergence_test) \ No newline at end of file diff --git a/convection_diffusion/README.md b/convection_diffusion/README.md index 969a59a8..3dba5045 100644 --- a/convection_diffusion/README.md +++ b/convection_diffusion/README.md @@ -4,3 +4,4 @@ - [Convection gaussian hill problem](validation/gaussian_hill_explicit) - [Convection-Diffusion gaussian hill problem](validation/gaussian_hill_with_diffusion_explicit) - [Rotating pulse problem](validation/rotating_pulse_explicit) +- [Space and time convergence tests](validation/space_time_convergence_test) diff --git a/convection_diffusion/validation/README.md b/convection_diffusion/validation/README.md index dce7bd25..a11aba47 100644 --- a/convection_diffusion/validation/README.md +++ b/convection_diffusion/validation/README.md @@ -5,3 +5,4 @@ This folder contains the validation cases: - [Convection gaussian hill problem](gaussian_hill_explicit) - [Convection-Diffusion gaussian hill problem](gaussian_hill_with_diffusion_explicit) - [Rotating pulse problem](rotating_pulse_explicit) +- [Space and time convergence tests](space_time_convergence_test) diff --git a/convection_diffusion/validation/space_time_convergence_test/README.md b/convection_diffusion/validation/space_time_convergence_test/README.md new file mode 100644 index 00000000..15517a85 --- /dev/null +++ b/convection_diffusion/validation/space_time_convergence_test/README.md @@ -0,0 +1,39 @@ +# Space and time convergence tests + +**Author:** [Riccardo Tosi](https://github.com/riccardotosi) + +**Kratos version:** 9.0 + +**Source files:** [section 2.7 of [1]](https://github.com/KratosMultiphysics/Documentation/blob/master/Resources_files/convection_diffusion_explicit_elements/Eulerian_convection_diffusion_explicit_element.pdf) + +## Space convergence + +We solve the transient convection diffusion equation + and validate its reference implementation. We refer to section 2.7.1 of [1] for details. + +We validate the implementation by computing the norm of the error as , where is the mesh size, and are the analytic and FEM solutions, respectively. + +

+ velocity +

+ +The figure shows that the error converges as expected for both quasi-static ASGS and quasi-static OSS. + +## Time convergence + +We solve the transient convection diffusion equation + and validate its reference implementation. We refer to section 2.7.2 of [1] for details. + +The analytic solution at time is . Therefore, it is possible to compute the norm of the error as +, where is the mesh size, and are the analytic and FEM solutions, respectively. It is expected to obtain an order four accuracy for the Runge-Kutta 4 time integration scheme. + +

+ velocity +

+ +The figure shows that the time accuracy is of order four, as expected. + + +## References + +[1] Tosi, R. (2020). Eulerian convection diffusion explicit elements (p. 27). p. 27. Retrieved from https://github.com/KratosMultiphysics/Documentation/blob/master/Resources_files/convection_diffusion_explicit_elements/Eulerian_convection_diffusion_explicit_element.pdf \ No newline at end of file diff --git a/convection_diffusion/validation/space_time_convergence_test/convergence_error_convection_diffusion_explicit_solution.jpg b/convection_diffusion/validation/space_time_convergence_test/convergence_error_convection_diffusion_explicit_solution.jpg new file mode 100644 index 00000000..e449deb5 Binary files /dev/null and b/convection_diffusion/validation/space_time_convergence_test/convergence_error_convection_diffusion_explicit_solution.jpg differ diff --git a/convection_diffusion/validation/space_time_convergence_test/convergence_error_time_convection_diffusion_bar.jpg b/convection_diffusion/validation/space_time_convergence_test/convergence_error_time_convection_diffusion_bar.jpg new file mode 100644 index 00000000..a1b1bdf4 Binary files /dev/null and b/convection_diffusion/validation/space_time_convergence_test/convergence_error_time_convection_diffusion_bar.jpg differ