TimeAdvanceBDFNavierStokes.hpp

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    Copyright (C) 2010 EPFL, Politecnico di Milano, Emory University

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/*!
    @file
    @brief File containing a class for an easy handling of different order time
            discretizations/extrapolations BDF based specific for the Navier-Stokes problem

    @date 01-04-2003
    @author Alessandro Veneziani <ale@mathcs.emory.edu>

    @contributor Laura Cattaneo
    @mantainer Laura Cattaneo

 */

#ifndef _BDF_NS_TEMPLATE_H
#define _BDF_NS_TEMPLATE_H

#include <string>
#include <iostream>
#include <algorithm>

#include <lifev/core/filter/GetPot.hpp>
#include <lifev/core/fem/TimeAdvanceBDF.hpp>


namespace LifeV
{

//! \class TimeAdvanceBDFNavierStokes
/*!
    @author Alessandro Veneziani
    @see Van Kan, Prohl, Guermond

    This class implements an easy handling of different order time discretizations/extrapolations
    Bdf based specific for the Navier-Stokes problem.

    The idea is to couple a Bdf of order q with a pressure incremental approach of order q-1.

    If q=1, we still have an incremental pressure treatment.

    At the moment, the couple BDF of order q + extrapolation of order q seems unstable

 */

template<typename VectorType = VectorEpetra >
class TimeAdvanceBDFNavierStokes
{
public:


    //! @name Public Types
    //@{

    typedef VectorType                          vector_Type;

    //@}


    //! @name Constructor & Destructor
    //@{

    //! Constructor
    TimeAdvanceBDFNavierStokes();

    //! Destructor
    ~TimeAdvanceBDFNavierStokes() { }

    //@}

    //! @name Set Methods
    //@{

    //! Setup the bdf velocity and the bdf pressure
    /*!
        @param order Order q of the bdf
     */
    void setup ( const UInt order );

    //@}

    //! @name Methods
    //@{

    //! Show the contents of the object
    void showMe() const;

    //! The method returns the Bdf velocity
    /*!
        @return Reference to a new Bdf template which holds the velocity field
     */
    TimeAdvanceBDF<VectorType>& bdfVelocity()
    {
        return M_bdfVelocity;
    }

    //! The method returns the Bdf pressure
    /*!
        @return Reference to a new Bdf template which holds the pressure
     */
    TimeAdvanceBDF<VectorType>& bdfPressure()
    {
        return M_bdfPressure;
    }

    //@}

private:

    //! Bdf velocity
    TimeAdvanceBDF<VectorType> M_bdfVelocity;

    //! Bdf pressure
    TimeAdvanceBDF<VectorType> M_bdfPressure;
};


// ===================================================
// Constructors
// ===================================================
template<typename VectorType>
TimeAdvanceBDFNavierStokes<VectorType>::TimeAdvanceBDFNavierStokes()
    :
    M_bdfVelocity( ),
    M_bdfPressure( )
{}


template<typename VectorType>
void
TimeAdvanceBDFNavierStokes<VectorType>::setup ( const UInt order )
{
    M_bdfVelocity.setup ( order, 1 );
    M_bdfPressure.setup ( std::max ( UInt ( 1 ), order - 1 ), 1 );
}

// ===================================================
// Methods
// ===================================================
template<typename VectorType>
void
TimeAdvanceBDFNavierStokes<VectorType>::showMe() const
{
    std::cout << " *** Bdf velocity: " << std::endl;
    M_bdfVelocity.showMe();
    std::cout << " *** Bdf pressure: " << std::endl;
    M_bdfPressure.showMe();
}


}// Namespace LifeV

#endif /* _BDF_NS_TEMPLATE_H */