strip

index.php:

$smarty = new Smarty;
$smarty->assign('articleTitle', "Grandmother of\neight makes\t    hole in one.");
$smarty->display('index.tpl');

index.tpl:

{$articleTitle}
{$articleTitle|strip}
{$articleTitle|strip:" "}

OUTPUT:

Grandmother of
eight makes        hole in one.
Grandmother of eight makes hole in one.
Grandmother of eight makes hole in one.