There are two ways you can export a terrain, either as a Heightfield (EXR or TER format), or as Geometry (OBJ or FBX format). Since you want an "array of 2d values" you basically want a heightfield, and while EXR might not be directly supported by your simulation software, you should be able to convert to something that will be.
The export process for heightfields varies slightly depending on how you build your terrain. If you are using heightfields already in Terragen (e.g. Heightfield Generate), you can simply right-click the node and Save As to get a heightfield version of it. If you are using Procedural shaders (e.g. Power Fractal, Alpine Fractal, etc.), you will need to convert into a heightfield format to export. So you'd create a new Heightfield Generate and plug the last node in your terrain network into the Shader input of the Heightfield Generate, then set the size, resolution, and position parameters to cover the area you want to export, click Generate when that's done, and then again right-click and Save As. During save you specify the output format (EXR), file name, and location.
For normals, if you get the Professional version you'll have access to a Normals render element, I'm not 100% sure that's what you want, but it's available. There is also a "visualize normals" shader node which may be appropriate.
For the simple 2D rectangular top-down view, just move your camera up above the terrain and point it down, or use an Orthographic camera with appropriate settings.
You can test most of this in the Free version, with the exception of the Render Elements. You can apply for a 30 day evaluation license of Professional if you need to test that.
- Oshyan