Collocated grid
From CFD-Wiki
In collocated grid storage all flow variables are stored at the same locations.
Here we should write more about odd-even decoupling, Rhie-Chow interpolation etc.
References
Rhie, C. M. and Chow, W. L. (1983), "Numerical study of the turbulent flow past an airfoil with trailing edge separation", AIAA Journal, vol. 21, pp. 1525-1532, 1983.