[Nek5000-users] Spectral method with Nek

All, I was wondering if the following statement is true or false: "If a single element is used for the whole domain then one can claim the Nek simulation is spectral instead of spectral element". Based on this, I carried out DNS on cavity for relatively large Reynolds numbers and I was not able to capture the instability mechanisms with one element (even when I increased the power of polynomial to 12 or 18). While I'm not surprised, I just wanted to see if anyone else has a similar experience. As a side question, why Nek utilizes Legendre polynomials instead of Chebyshev for each element? Is this because we're also interested in modeling non-uniformly spaced nodes? Best, Saleh