*Leon Ehrenpreis*

- Published in print:
- 2003
- Published Online:
- September 2007
- ISBN:
- 9780198509783
- eISBN:
- 9780191709166
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198509783.003.0008
- Subject:
- Mathematics, Mathematical Physics

This chapter deals with various questions which are related to the Radon transform, for example, the analog for forms, Selberg's trace formula. It gives a sharpening of the classical Euler-Maclaurin ...
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This chapter deals with various questions which are related to the Radon transform, for example, the analog for forms, Selberg's trace formula. It gives a sharpening of the classical Euler-Maclaurin sum formula — it is regarded here as a “truncated Poisson summation formula” and other truncations are introduced. The chapter suggests a “compact trick” which shows how to pass from compact to noncompact forms regarding the Plancherel formula.Less

This chapter deals with various questions which are related to the Radon transform, for example, the analog for forms, Selberg's trace formula. It gives a sharpening of the classical Euler-Maclaurin sum formula — it is regarded here as a “truncated Poisson summation formula” and other truncations are introduced. The chapter suggests a “compact trick” which shows how to pass from compact to noncompact forms regarding the Plancherel formula.

*Bijan Mohammadi and Olivier Pironneau*

- Published in print:
- 2009
- Published Online:
- February 2010
- ISBN:
- 9780199546909
- eISBN:
- 9780191720482
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199546909.003.0003
- Subject:
- Mathematics, Mathematical Physics

This chapter describes the governing equations considered throughout the book. The equations of fluid dynamics are recalled, together with the k-epsilon turbulence model, which is used later on for ...
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This chapter describes the governing equations considered throughout the book. The equations of fluid dynamics are recalled, together with the k-epsilon turbulence model, which is used later on for high Reynolds number flows when the topology of the answer is not known. The fundamental equations of fluid dynamics are recalled; this is because applied OSD for fluids requires a good understanding of the state equation: Euler and Navier–Stokes equations in this case, with and without turbulence models together with the inviscid and/or incompressible limits. The chapter recalls wall-laws also used for OSD as low complexity models. By wall-laws domain decomposition with a reduced dimension model near the wall is understood. In other words, there is no universal wall-laws and when using a wall-function, it needs to be compatible with the model used far from the wall. Large eddy simulation is giving a new life to the wall-functions especially to simulate high-Reynolds external flows.Less

This chapter describes the governing equations considered throughout the book. The equations of fluid dynamics are recalled, together with the k-epsilon turbulence model, which is used later on for high Reynolds number flows when the topology of the answer is not known. The fundamental equations of fluid dynamics are recalled; this is because applied OSD for fluids requires a good understanding of the state equation: Euler and Navier–Stokes equations in this case, with and without turbulence models together with the inviscid and/or incompressible limits. The chapter recalls wall-laws also used for OSD as low complexity models. By wall-laws domain decomposition with a reduced dimension model near the wall is understood. In other words, there is no universal wall-laws and when using a wall-function, it needs to be compatible with the model used far from the wall. Large eddy simulation is giving a new life to the wall-functions especially to simulate high-Reynolds external flows.