Results 5 issues of Ilya

# Modulus Pull Request ## Description ## Checklist - [ ] I am familiar with the [Contributing Guidelines](https://github.com/NVIDIA/modulus-sym/blob/main/CONTRIBUTING.md). - [ ] New or existing tests cover these changes. - [...

# Modulus Pull Request ## Description ## Checklist - [ ] I am familiar with the [Contributing Guidelines](https://github.com/NVIDIA/modulus-sym/blob/main/CONTRIBUTING.md). - [ ] New or existing tests cover these changes. - [...

In some cases it is better to use incompressible NS and Euler equation uses way less memory

enhancement