R/sandbox/_sandbox.R

In dCraigJones/gravity: graphic library and calculator for partially-full open-channel flow in circular pipelines

  draw_stevens_schultzbach <- function(y, v, ddog, d=8, s=0.33/100) {
    xx <- calc_hyd_radius(y-ddog, d, s)
    yy <- v

    fit <- lm(yy~xx)
    b <- coef(fit)[2]

    C <- b/1.486

    n <- sqrt(s)/C

    y <- seq(0,d,length.out=1000)

    y_ <- y-ddog
    theta <- 2*acos(1-2*y_/d)
    area <- d^2/8*(theta-sin(theta))
    perimeter <- 0.5*theta*d
    r <- area/perimeter

    q_gpm <- 448.8*1.49/n*(area/12^2)*(r/12)^(2/3)*sqrt(s)
    v_fps <- (q_gpm/448.8)/(area/144)

    lines(v_fps, y, lty=2)
  }





  min.rmse <- min(curve[,2], na.rm=TRUE)
  index <- which(min.rmse==curve[,2])
  depth <- seq(0,8,length.out=50)[index]

  xx <- calc_hyd_radius(y, d-depth, s)
  yy <- v


  fit <- lm(yy~xx)

  b <- coef(fit)[2]

  C <- b/1.486

  n <- sqrt(s)/C

  draw_manning(d-depth, n, s)