If df is already ordered, you can simply do:
df$inst <- c(object1, object1, object2)
Or in a tidyverse way,
df <- df |>
add_column(inst = c(object1, object1, object2))
Here is a reprex:
object1 <- 1:10
object2 <- 101:110
df <- data.frame(New_column = c(rep("West", 20), rep("Atlantic constrained", 10)))
df$inst1 <- c(object1, object1, object2)
library(tibble)
df <- df |>
add_column(inst2 = c(object1, object1, object2))
df
#> New_column inst1 inst2
#> 1 West 1 1
#> 2 West 2 2
#> 3 West 3 3
#> 4 West 4 4
#> 5 West 5 5
#> 6 West 6 6
#> 7 West 7 7
#> 8 West 8 8
#> 9 West 9 9
#> 10 West 10 10
#> 11 West 1 1
#> 12 West 2 2
#> 13 West 3 3
#> 14 West 4 4
#> 15 West 5 5
#> 16 West 6 6
#> 17 West 7 7
#> 18 West 8 8
#> 19 West 9 9
#> 20 West 10 10
#> 21 Atlantic constrained 101 101
#> 22 Atlantic constrained 102 102
#> 23 Atlantic constrained 103 103
#> 24 Atlantic constrained 104 104
#> 25 Atlantic constrained 105 105
#> 26 Atlantic constrained 106 106
#> 27 Atlantic constrained 107 107
#> 28 Atlantic constrained 108 108
#> 29 Atlantic constrained 109 109
#> 30 Atlantic constrained 110 110
Created on 2022-07-15 by the reprex package (v2.0.1)