use Sort::Key::Natural qw(natsort);
my @sorted = natsort @data;
[download]

use Benchmark qw(cmpthese);

use Sort::Naturally qw(nsort);
use Sort::Key::Natural qw(natsort);

my @data = grep !/^\s*$/, <DATA>;
chomp(@data);

cmpthese(-10, { sn => sub { my @s = nsort @data },
                skn => sub { my @s = natsort @data } } );

__DATA__

K-2-D-10A
K-2-D-10C
K-2-D-10D
...
[download]

$ perl bm.pl
      Rate   sn  skn
sn  45.0/s   -- -79%
skn  216/s 381%   --
[download]

FYI, since we're running benckmarks:

#!/usr/bin/perl
use warnings;
use strict;
use Benchmark 'cmpthese';
use Sort::Naturally 'nsort';
use Sort::Key::Natural 'natsort';

my @data = grep /\S/, <DATA>;

sub normalize_digits {
    my ( $key ) = @_;
    $key =~ s/(\d+)/sprintf '%03d', $1/eg;
    return $key;
    }

cmpthese -10, {
    SN_nsort    => sub { my @s = nsort   @data },
    SKN_natsort => sub { my @s = natsort @data },
    GRT_pack    => sub { my @s =
        map unpack( 'x3 a*', $_ ),
        sort
        map pack( 'n a a*', /(\d+)([A-Z])/, $_ ),
        @data
        },
    ST_sub      => sub { my @s =
        map  { $_->[ 0 ] }
        sort { $a->[ 1 ] cmp $b->[ 1 ] }
        map  { [ $_, normalize_digits( $_ ) ] }
        @data
        },
    GRT_sub     => sub { my @s =
        map { local $_ = $_; s/^.*\0//; $_ }
        sort
        map { normalize_digits( $_ ) . "\0$_" }
        @data
        },
    GRT_sprintf => sub { my @s =
        map { s/-0+/-/g; $_ }
        sort
        map { s/(\d+)/sprintf '%03d', $1/eg; $_ }
        @data
        },
    };

__DATA__

K-2-D-10A
K-2-D-10C
K-2-D-10D
K-2-D-10E
K-2-D-10F
K-2-D-10G
K-2-D-11A
etc.
etc.
[download]

Which gave me these results:

              Rate SN_nsort SKN_natsort    ST_sub   GRT_sub GRT_sprint
+f GRT_pack
SN_nsort    64.6/s       --        -81%      -90%      -91%        -93
+%     -97%
SKN_natsort  341/s     427%          --      -47%      -51%        -62
+%     -82%
ST_sub       642/s     893%         88%        --       -7%        -29
+%     -67%
GRT_sub      694/s     973%        104%        8%        --        -23
+%     -64%
GRT_sprintf  900/s    1292%        164%       40%       30%          -
+-     -53%
GRT_pack    1928/s    2883%        466%      200%      178%        114
+%       --
[download]

:-)

well, Sort::Key::Natural is a general solution that doesn't make any assumption about the strings passed. For instance it doesn't have a limit on the number of groups or on the size of the numbers that can be embedded in the strings.

But if you know the data is of the format /^K-2-D-\d+\w$/ and want to create a sorter taking advantage of it, a Sort::Key based solution is still the fastest:

use Sort::Key::Multi 'ii_keysort';
...

cmpthese(-10, {
                ...
                SKMii => sub {
                    my @s = ii_keysort { /(\d+)([A-Z])/; $1, ord $2 } 
+@data
                } } );
[download]

gives me:

SN_nsort    46.9/s       --        -81%   -89%    -90%        -92%    
+ -96%  -96%
SKN_natsort  244/s     420%          --   -43%    -47%        -58%    
+ -79%  -81%
ST_sub       427/s     812%         75%     --     -7%        -27%    
+ -62%  -66%
GRT_sub      460/s     881%         89%     8%      --        -22%    
+ -60%  -64%
GRT_sprintf  587/s    1152%        141%    37%     28%          --    
+ -48%  -54%
GRT_pack    1136/s    2323%        366%   166%    147%         94%    
+   --  -11%
SKMii       1272/s    2614%        422%   198%    177%        117%    
+  12%    --
[download]