Trouble initializing a $scope variable with ng-init in my HTML

I am trying to initialize $scope.selectedModel to model1with ng-init. However, the following HTML fails to accomplish this:

<div class="productImage">
    <div class="imageGallery" ng-init="selectedModel='model1'">

        <div ng-repeat="mod in pTab" ng-if="modelIsActive(mod)">
            <div ng-repeat="img in mod.galleryImages">
                <img class="overviewProductImage" ng-src="{{img.image}}" ng-if="productImageIsActive(img, $index)"/>
            </div>
        </div>  

    </div>
</div>

And here's the modelIsActive method that uses selectedModel:

$scope.modelIsActive = function (tab) {
            return tab.model== $scope.selectedModel;
}

Eventually I will want to use ng-init="selectedModel= mod.model" but when that didn't work I substituted the simple string 'model1' and found it still wasn't initializing selectedModelto that string.

How can I use ng-init to set $scope.selectedModel? Or should I be using something else? Do I need to use $watch or something similar?

Thank you very much for your time.