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Converted document INTEGRATION DEMONSTRATION
INTEGRATION DEMONSTRATION

This code demonstrates integration of pressure coefficient data in a file to calculate the pitching moment, which is the moment about the quarter-chord of the airfoil.
PROGRAM Pitching_Moment_Cp
    IMPLICIT NONE
    REAL, DIMENSION(1:800,1:2):: points
    REAL :: ref, PM_L, PM_R, PM_M, PM_T, PM_S
    INTEGER :: I,J,iost
    OPEN (unit=10, file=’data.prn’,&
    & status=’old’)
    DO I=1,800
        READ(10,*,IOSTAT=iost)(points(I,J),J=1,2)
    END DO
    IF (iost==0) THEN
        WRITE(*,*) ’No EOF Encountered’
    ELSEIF (iost<0) THEN
        WRITE(*,*) ’EOF encountered’
        STOP
    ELSE
        WRITE(*,*) ’error in execution. iost=’, iost
        STOP
    END IF
	
    WRITE(*,*) ’What is your reference point (as a real number)?’
    READ(*,*) ref
	
    CALL LT_PT(points, ref,  PM_L)
    CALL RT_PT(points, ref, PM_R)
    CALL md_PT(points, ref, PM_M)
    CALL Trap(points, ref, PM_T)
    CALL Simpsons(points, ref, PM_S)

    WRITE(*,*) ’The Pitching Moment Coefficient by the Left Hand Rule=’, PM_L
    WRITE(*,*) ’The Pitching Moment Coefficient by the Right Hand Rule=’, PM_R
    WRITE(*,*) ’The Pitching Moment Coefficient by the Midpoint Rule=’, PM_M
    WRITE(*,*) ’The Pitching Moment Coefficient by the Trapazoidal Rule=’, PM_T
    WRITE(*,*) "The Pitching Moment Coefficient by the Simpson’s Rule=", PM_S
	
    CONTAINS
        subroutine LT_PT(points, ref, PM_L)
            REAL, intent(in), dimension(1:800,1:2) :: points
            REAL, intent(in):: ref
            REAL, intent(out):: PM_L
            INTEGER :: I
            PM_L=0
            DO I= 1,800-1
                PM_L=PM_L+ ( ref - points(I,1) ) * points(I,2) * &
                 ( points(I+1,1) - points(I,1) )
            END DO
        END subroutine LT_PT
		
		
        subroutine RT_PT(points, ref, PM_R)
            REAL, intent(in), dimension(1:800,1:2) :: points
            REAL, intent(in):: ref
            REAL, intent(out):: PM_R
            INTEGER :: I
            PM_R=0
            DO I=1,800-1
                PM_R=PM_R + ( ref - points(I,1) ) * points(I+1,2) * &
                  &( points(I+1,1) - points(I,1) )
            END DO
        END subroutine RT_PT
		
		
        subroutine md_PT(points, ref, PM_M)
            REAL, intent(in), dimension(1:800,1:2) :: points
            REAL, intent(in):: ref
            REAL, intent(out):: PM_M
            INTEGER :: I
            PM_M=0
            DO I=1,800-1
                PM_M=PM_M + ( ref - points(I,1) ) * ( points(I+1,2)&
                  & + points(I,2) ) * .5 *&
                & ( points(I+1,1) - points(I,1) )
            END DO
        END subroutine md_PT
		
		
        subroutine Trap(points, ref, PM_T)
            REAL, intent(in), dimension(1:800,1:2) :: points
            REAL, intent(in):: ref
            REAL, intent(out):: PM_T
            INTEGER :: I
            PM_T=0
            DO I=1,800-1
                PM_T= PM_T + ( ref - points(I,1) ) * ( points(I,2)&
                  & + points(I+1,2)) * .5 &
                  & * ( points(I+1,1) - points(I,1) )
            END DO
        END subroutine Trap