Stream-wise operator

Average

Average at stream-wise cell faces:

\[\vat{ \ave{ q }{ \gy } }{ j + \frac{1}{2} } = \frac{1}{2} \vat{q}{j} + \frac{1}{2} \vat{q}{j + 1}\]

Average at stream-wise cell centers:

\[\vat{ \ave{ q }{ \gy } }{ j } = \frac{1}{2} \vat{q}{j - \frac{1}{2}} + \frac{1}{2} \vat{q}{j + \frac{1}{2}}\]

Differentiation

Differentiation at stream-wise cell faces:

\[\vat{ \dif{ q }{ \gy } }{ j + \frac{1}{2} } = - \vat{q}{j} + \vat{q}{j + 1}\]

Differentiation at stream-wise cell centers:

\[\vat{ \dif{ q }{ \gy } }{ j } = - \vat{q}{j - \frac{1}{2}} + \vat{q}{j + \frac{1}{2}}\]

Summation

Summation of a quantity defined at stream-wise cell faces:

\[\sumyf q \equiv \vat{q}{\frac{1}{2}} + \vat{q}{\frac{3}{2}} + \cdots + \vat{q}{\ny - \frac{3}{2}} + \vat{q}{\ny - \frac{1}{2}}\]

Summation of a quantity defined at stream-wise cell centers:

\[\sumyc q \equiv \vat{q}{1} + \vat{q}{2} + \cdots + \vat{q}{\ny - 1} + \vat{q}{\ny}\]