Gresho-Vortex-test-in-2D.md

+# Gadget-2 SPH, Cubic spline kernel, eta=1.234
+![gadget2_GreshoVortex_2D_11_2D](/uploads/d5c23160e595788bd2c8017637f4dd23/gadget2_GreshoVortex_2D_11_2D.png)
+
+# Pressure-Entropy SPH, Cubic spline kernel, eta=1.234
+![hopkins_GreshoVortex_2D_11_2D](/uploads/dc8ff3998f888415d864e9c538b1a514/hopkins_GreshoVortex_2D_11_2D.png)
+
+# GIZMO, Cubic spline kernel, eta=1.235, exact Riemann solver
+![gizmo_GreshoVortex_2D_11_2D](/uploads/3c6fb93ee99cf8bef7faef514c0ed141/gizmo_GreshoVortex_2D_11_2D.png)
\ No newline at end of file